The hidden dangers of staying home: a London trauma unit experience of lockdown during the COVID-19 virus pandemic

INTRODUCTION

The COVID-19 pandemic resulted in reconfiguration of the NHS. Elective services were stopped and trauma services focused on decreasing patient-clinician interactions and managing injuries nonoperatively wherever possible. The everyday life of the general public changed dramatically with the introduction of a national lockdown to prevent the spread of COVID-19. This paper looks at the experience of a South West London trauma unit.

MATERIALS AND METHODS

All patients reviewed in fracture clinic and by the orthopaedic on-call team between 23 March to 23 April 2020 were included. Data on the mechanism of injury and whether this was a usual activity, the injury sustained and its management were collected.

RESULTS

A total of 167 trauma injuries were seen, compared with 735 new patients with injuries in the previous month. The number of trauma operations completed decreased by 38%; 55% of injuries occurred inside the home and 44% outside the home during daily exercise. Some 31% of injuries were secondary to a new activity taken up during lockdown. Three open fractures and two polytrauma cases were seen that would have normally been managed at the local major trauma centre.

CONCLUSION

Overall, both the number of injuries seen and trauma operations completed during the enforced lockdown decreased. This is probably due to a change in the way the general public are living their lives, and the reconfigurations within the NHS in response to the COVID-19 pandemic. This is an interesting time within trauma and orthopaedic departments, as they continue to adapt to the changing injuries and working environment.

Engineering gibberellin metabolism in Solanum nigrum L. by ectopic expression of gibberellin oxidase genes

Gibberellins (GAs) control many aspects of plant development, including seed germination, shoot growth, flower induction and growth and fruit expansion. Leaf explants of Solanum nigrum (Black Nightshade; Solanaceae) were used for Agrobacterium-mediated delivery of GA-biosynthetic genes to determine the influence of their encoded enzymes on the production of bioactive GAs and plant stature in this species. Constructs were prepared containing the neomycin phosphotransferase (nptII) gene for kanamycin resistance as a selectable marker, and the GA-biosynthetic genes, their expression under the control of the CaMV 35S promoter. The GA-biosynthetic genes comprised AtGA20ox1, isolated from Arabidopsis thaliana, the product from which catalyses the formation of C(19)-GAs, and MmGA3ox1 and MmGA3ox2, isolated from Marah macrocarpus, which encode functionally different GA 3-oxidases that convert C(19)-GAs to biologically active forms. Increase in stature was observed in plants transformed with AtGA20ox1, MmGA3ox2 and MmGA3ox1 + MmGA3ox2, their presence and expression being confirmed by PCR and RT-PCR, respectively, accompanied by an increase in GA(1) content. Interestingly, MmGA3ox1 alone did not induce a sustained increase in plant height, probably because of only a marginal increase in bioactive GA(1) content in the transformed plants. The results are discussed in the context of regulating plant stature, since this strategy would decrease the use of chemicals to promote plant growth.

Is revision surgery following lower-limb amputation a worthwhile procedure? A retrospective review of 71 cases

There is little written about the value of revision surgery on lower-limb amputations. We report on 71 revision amputation procedures performed by a single surgeon in this retrospective analysis. The majority of our revisions (61%) were in amputees who had suffered trauma. We judged success from a surgical and a rehabilitation perspective using scoring systems. Revisions for bony and soft-tissue pathology had good outcomes from a surgical (85% and 82%) and a rehabilitation perspective. Revisions for infection had satisfactory results from a surgical perspective (73%) but less so from a rehabilitation perspective (25%). The results of the revisions for pain were poor showing surgical success only 50% of the time where a neuroma was suspected and only 25% when there was no apparent cause. There was little or no improvement in rehabilitation in both the pain groups. Revision surgery for certain pathologies gives a good surgical outcome and can improve pain and mobility status. Patient selection for surgery is key and evaluation by a multidisciplinary team is recommended.

Pelvic and acetabular fractures in the United Kingdom: a continued public health emergency

In 1996 the quality of the early management of 100 consecutive patients referred to the SW Thames regional pelvic and acetabular unit between 1989 and 1992 was studied. The management of these patients was assessed in four specific areas, and guidelines were laid down. It was found that in 56% of patients the early management did not meet these suggested standards, with 34% having deficiencies in more than one area. These results were presented and published. Five years later, the early management of a further 100 consecutive referrals was assessed using these same guidelines, in order to close the audit loop. The treatment of 57% of patients still did not reach the guideline standards, but the number with problems in more than one area fell to 20%. There has been improvement in the early management of pelvic and acetabular injuries. The use of external fixation in cases of severe haemorrhage increased, but frames were often poorly applied. Early communication with the specialist centre was encouraged but unfortunately there was still an unacceptable delay in referral. The frequency of delayed referral actually increased during the 5 years between study groups.

The effects of topical ocular application of 0.25% demecarium bromide on serum acetylcholinesterase levels in normal dogs

OBJECTIVE

To assess the effects of topical ocular application of 0.25% demecarium bromide on serum acetylcholinesterase (AChE) levels in normal dogs.

ANIMALS

Nine adult mixed breed dogs weighing between 18 and 27 kg.

PROCEDURES

Fifty micro L of 0.25% demecarium bromide were applied to one eye of each dog every 8 h for 6 days. Blood was analyzed for AChE levels prior to commencement of eye drops, and at 45 min, 1 h 45 min, 4 h 45 min, 1 day, 3 days, and 7 days following commencement of eye drops using a 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) reaction.

RESULTS

Acetylcholinesterase levels declined over the first 24 h following commencement of demecarium administration in most dogs. This decline was highly variable and was statistically significant by 24 h. In some individuals AChE levels were suppressed to levels approaching clinical toxicity. By day 3 AChE levels had risen to levels above baseline in most dogs.

CONCLUSIONS

Topical ocular application of demecarium causes transient suppression of systemic acetylcholinesterase levels in most dogs. Acetylcholinesterase levels generally do not fall to toxic levels, but may do so in certain individuals. Demecarium bromide eye drops generally do not cause AChE toxicity, but dogs receiving such therapy should be monitored for signs of AChE toxicity, and concomitant use of other AChE inhibitors should be avoided.

Effects of antibiotics on morphologic characteristics and migration of canine corneal epithelial cells in tissue culture

OBJECTIVE

To determine effects of commonly used ophthalmic antibiotics on cellular morphologic characteristics and migration of canine corneal epithelium in cell culture.

SAMPLE POPULATION

Corneal epithelial cells harvested from corneas of 12 euthanatized dogs and propagated in cell culture.

PROCEDURE

Cells were treated with various antibiotics after a defect was created in the monolayer. Cellular morphologic characteristics and closure of the defect were compared between antibiotic-treated and control cells.

RESULTS

Cells treated with ciprofloxacin and cefazolin had the greatest degree of rounding, shrinkage, and detachment from plates. Cells treated with neomycin-polymyxin B-gramicidin and gentamicin sulfate had rounding and shrinkage but with less detachment. Cells treated with tobramycin and chloramphenicol grew similarly to control cells. On the basis of comparisons of defect circumference between control cells and cells exposed to antibiotics, tobramycin affected cellular migration the least.

CONCLUSIONS AND CLINICAL RELEVANCE

Effects of ciprofloxacin and cefazolin on morphologic characteristics of canine corneal epithelial cells in vitro should be taken into consideration before using these antibiotics for first-line of treatment for noninfected ulcers. Of the antibiotics tested that have a primarily gram-negative spectrum of coverage, gentamicin inhibited corneal epithelial cell migration and had greater cytopathologic effects than tobramycin did. For antibiotics with a gram-positive coverage, chloramphenicol had no cytopathologic effects on cells in comparison to cefazolin, which caused most of the cells to shrink and detach from the plate. Polymyxin B-neomycin-gramicidin was midrange in its effects on cellular morphologic characteristics and migration.

Effects of topical application of a 2% solution of dorzolamide on intraocular pressure and aqueous humor flow rate in clinically normal dogs

OBJECTIVE

To evaluate effects of topical application of a 2% solution of dorzolamide on intraocular pressure (IOP) and aqueous humor flow rate in clinically normal dogs.

ANIMALS

15 Beagles.

PROCEDURE

The IOP was measured in both eyes of all dogs for 3 days to determine baseline values. In a single-dose study, 50 microl of dorzolamide or control solution was applied in both eyes at 7:00 AM, and IOP was measured 7 times/d. In a multiple-dose study, dorzolamide or control solution was applied to both eyes 3 times/d for 6 days, and IOP was measured 4 times/d during treatment and for 5 days after cessation of treatment. Aqueous humor flow rate was measured for all dogs fluorophotometrically prior to treatment and during the multiple-dose study.

RESULTS

In the single-dose study, dorzolamide significantly decreased IOP from 30 minutes to 6 hours after treatment. Mean decrease in IOP during this time span was 3.1 mm Hg (18.2%). Maximal decrease was detected 6 hours after treatment (3.8 mm Hg, 22.5%). In the multiple-dose study, dorzolamide decreased IOP at all time points, and maximal decrease was detected 3 hours after treatment (4.1 mm Hg, 24.3%). Mean aqueous humor flow rate decreased from 5.9 to 3.4 microl/min (43%) after treatment in the dorzolamide group.

CONCLUSIONS AND CLINICAL RELEVANCE

Topical application of a 2% solution of dorzolamide significantly decreases IOP and aqueous humor flow rate in clinically normal dogs. Therefore, topical administration of dorzolamide should be considered for the medical management of dogs with glaucoma.

Fluorophotometric determination of aqueous humor flow rate in clinically normal dogs

OBJECTIVE

To determine aqueous humor flow rate in clinically normal dogs, using fluorophotometry.

ANIMALS

20 clinically normal Beagles.

PROCEDURE

A study was performed on 5 dogs to establish an optimal protocol for fluorophotometric determination of aqueous humor flow rate. This protocol then was used to measure aqueous humor flow rate in 15 dogs. Corneas were loaded with fluorescein by topical application, and corneal and aqueous humor fluorescein concentrations were measured 5, 6.5, and 8 hours after application. Concentration-versus-time plots were generated, and slopes and ratios of the fluorescein concentration in the cornea and aqueous humor from these graphs were used to calculate flow rates. Calculations were performed by use of automated software provided with the fluorophotometer and by manual computation, and the 2 calculation methods were compared.

RESULTS

The protocol established for the 5 dogs resulted in semilogarithmic and parallel decay of corneal and aqueous humor concentrations. Manually calculated mean +/- SD aqueous humor flow rates for left, right, and both eyes were 5.58 +/- 2.42, 4.86 +/- 2.49, and 5.22 +/- 1.87 microl/min, respectively, whereas corresponding flow rates calculated by use of the automated software were 4.54 +/- 3.08, 4.54 +/- 3.10, and 4.54 +/- 2.57 microl/min, respectively. Values for the left eye were significantly different between the 2 computation methods.

CONCLUSIONS AND CLINICAL RELEVANCE

Aqueous humor flow rates can be determined in dogs, using fluorophotometry. This technique can be used to assess pathologic states and medical and surgical treatments that alter aqueous humor dynamics.

Induction of dwarfism in transgenic Solanum dulcamara by over-expression of a gibberellin 20-oxidase cDNA from pumpkin

The gibberellin (GA) 20-oxidase (CmGA20ox1) from immature pumpkin seed produces predominantly inactive tricarboxylic acid GAs. We expressed CmGA20ox1 under the control of the CaMV 35S promoter in Solanum dulcamara to assess the usefulness of this gene for reducing GA content in transgenic plants. All transgenic plants obtained were semi-dwarfs with smaller, deep-green leaves and highly pigmented stems compared to the wild-type. Such transformants flowered earlier than the wild-type plants and produced more fruit and more seeds per fruit. The transgene was efficiently expressed, producing high levels of CmGA20ox1 transcript and protein. Furthermore, the concentration of GA(1) was reduced in leaves of the transformants to approximately 20% or less of that in the wild-type and to about 40% or less in stems. The concentrations of other 13-hydroxylated GAs were also reduced, except for the tricarboxylic acid, GA(17), which accumulated in the transformants due to 13-hydroxylation of GA(25). By contrast, the concentrations of non-13-hydroxylated GAs, GA(4) and GA(34), were not consistently reduced, indicating that the effect of expressing the pumpkin gene may not be predictable. Transcript abundance for a native GA 20-oxidase gene was higher in the leaves and stems of S. dulcamara transformed with the pumpkin gene than in wild-type, reflecting the feedback control of 20-oxidase gene expression that serves as a homeostatic mechanism for GAs.

Migration of the uncemented CLS acetabular component

The migration of uncemented press-fit CLS (Cementless Total Hip Replacement System) acetabular cups was measured retrospectively from standard anteroposterior pelvic radiographs using a digitizer and software specifically developed for this study. A radiographic and clinical review also were undertaken. There were 96 patients in the study group. The mean follow-up for radiographic review was 2.23 years, and the mean follow-up for clinical review was 3 years. Migration was measured in the cranial and medial directions. Mean migration of the cup at 2 years was 1.35 mm in the cranial direction and 2.15 mm in the medial direction. Radiographic appearances altered little over the study period. Fifty-five (57.3%) patients demonstrated bone ingrowth onto the prosthesis, predominantly in DeLee and Charnley zone 1. Twenty-one patients demonstrated nonprogressive sclerotic lines; no lucent lines were encountered. Statistical analysis showed a significant correlation between acetabular ingrowth and reduced cup migration in the medial direction (P = .011 at 5 years). There was no statistical relationship between migration of the cup and radiographic features or clinical outcome.

Migration of the uncemented CLS femoral component

The migration of uncemented CLS (Cementless Total Hip Replacement System) femoral stems was measured retrospectively from standard anteroposterior pelvic radiographs using a digitizer and software specifically designed for this study. The study population was comprised of 117 patients with 126 uncemented CLS femoral stems. All radiographs were reviewed and the incidence of thigh pain obtained by means of a questionnaire. The mean clinical follow-up was 3 years and the mean follow-up for radiographic review was 2.77 years. The mean femoral stem migration was 2 mm at 2 years and 3.66 mm at 7 years. Radiographic features varied little with no specific predictive features in patients with excessive early migration or those who complained of thigh pain. There was no statistical relationship between the presence of thigh pain and femoral stem migration.

Orbital plasmacytoma in a cat

An Abyssinian cat presented with epistaxis, melaena and retinal vascular changes. Plasma protein levels were markedly elevated and a monoclonal gammopathy was present on serum protein electrophoresis. Based on these laboratory findings, hyperviscosity syndrome was assumed to be responsible for the clinical signs. The cat responded initially to fluid therapy, but relapsed and then developed unilateral exophthalmia. The animal was euthanased and an extramedullary plasmacytoma of the right orbit was diagnosed at postmortem examination.

Gibberellin biosynthesis from gibberellin A12-aldehyde in endosperm and embryos of Marah macrocarpus

Soluble enzyme preparations from embryos and endosperm of Marah macrocarpus (previously Echinocystis macrocarpa) were incubated with [14C4]gibberellin(GA)12-aldehyde, [14C4]GA12, [14C1] GA9, 2,3-didehydro[14C1]GA9, [14C1]GA20, and [17-13C, 3H]GA5. Embryo preparations converted GA12-aldehyde, GA12, and GA9 to GA4 and GA7; 2,3-didehydroGA9 to GA7; GA5 to GA3; and GA20 (incompletely) to GA1 and GA60, but not to GA3. Endosperm preparations converted GA12-aldehyde and GA12 to GA15, GA24, and GA9, but, unlike embryo preparations, not to GA4 or GA7. However, GA4 and GA7 were formed from GA9 and GA7 was formed from 2,3-didehydroGA9. Metabolism of GA5 to GA3 and GA20 to GA1 was low. 2,3-DidehydroGA9 accumulated when GA9 was incubated with a desalted endosperm preparation. A cDNA clone (M3-8), selected from an embryo-derived cDNA library using a DNA fragment generated by reverse transcriptase polymerase chain reaction, was expressed in Escherichia coli. The fusion protein converted GA12 to GA9 (major) and GA25 (minor); GA53 was metabolized less effectively and only to GA44. Thus, the M3-8 protein is functionally similar to GA 20-oxidases from Arabidopsis thaliana, Spinacia oleracea, and Pisum sativum, but different from that from Cucurbita maxima seeds, to which its amino acid sequence is most closely related. mRNA hybridizing to M3-8 accumulated in embryos and endosperm of M. macrocarpus, but was absent in vegetative tissues.

Isolation and transcript analysis of gibberellin 20-oxidase genes in pea and bean in relation to fruit development

PCR was used with degenerate primers based on conserved amino acid sequences in gibberellin (GA) 20-oxidases to isolate cDNA clones for these enzymes from young seeds of pea (Pisum sativum) and developing embryos of French bean (Phaseolus vulgaris). One GA 20-oxidase cDNA (Ps27-12) was obtained from pea and three (Pv 15-11, Pv73-1 and Pv85-26) from bean. Their identities were confirmed by demonstrating that fusion proteins expressed in Escherichia coli exhibited GA 20-oxidase activity, converting [14C]GA12 to [14C]GA9. The intermediates in this three-step reaction, GA15 and GA24, were also identified as products. The expression proteins from three of the clones (Ps27-12, Pv15-11 and Pv73-1) were also shown to convert GA53 to GA20, as effectively as they did GA12. On the basis of transcript levels measured by northern blot analysis, the pea GA 20-oxidase gene is most highly expressed in young leaves, fully expanded internodes, very young seeds (until 4 days after anthesis) and expanding pods (from 3 days after anthesis at least until day 6). Expression in pods from 3-day-old unpollinated ovaries is higher than in those from pollinated ovaries. Treatment of unpollinated ovaries with GA3 to induce parthenocarpic fruit-set severely reduced the amount of GA 20-oxidase mRNA, whereas treatment with 2,4-D, although inducing fruit-set, did not reduce the levels of these transcripts. Plant decapitation above an unpollinated ovary resulted in very high levels of GA 20-oxidase mRNA in the pod. The three GA 20-oxidase genes from French bean showed very different patterns of expression: Pv 15-1 was expressed in the roots, young leaves, and developing seeds, but most highly in immature cotyledons, while Pv73-1 has a similar expression pattern to Ps27-12, with transcripts found only in young seeds and young leaves, where it was particularly abundant. Transcripts corresponding to Pv85-26 were detected in developing seeds, and just traces in the young leaves. Southern blot analysis indicated that the bean GA 20-oxidases are each encoded by single-copy genes, whereas one more gene, homologous to Ps27-12, could also exist in pea.

Long-term and high-dose trials of enzyme replacement therapy in the canine model of mucopolysaccharidosis I

Enzyme replacement is a potential therapy for mucopolysaccharidosis I (MPS I), a lysosomal storage disorder caused by alpha-L-iduronidase deficiency. Previous work showed improvement in the tissues of MPS I dogs treated intravenously for 3 months with recombinant human alpha-L-iduronidase (25,000 units or approximately 0.1 mg/kg/week). We have now treated an MPS I-affected dog for 13 months to assess the clinical effects of enzyme replacement. The treated dog gained more weight, was more active, and had less joint stiffness than the untreated littermate. Biochemical and histologic studies demonstrated uptake of alpha-L-iduronidase and decreased lysosomal storage in the liver, kidney, spleen, lymph nodes, synovium, adrenals, and lungs. The brain had detectable enzyme activity and decreased glycosaminoglycan storage although histologic improvement was not evident. Cartilage and heart valve did not show any detectable improvement. A fivefold higher dose (approximately 0.5 mg/kg) administered five times over 10 days to two other dogs resulted in higher tissue enzyme activity and similarly decreased glycosaminoglycan storage and excretion. Antibodies to human alpha-L-iduronidase were induced in all treated dogs and may be associated with immune complex deposition and proteinuria. Recombinant canine alpha-L-iduronidase also induced antibody formation to a similar degree. The results support the conclusion that enzyme replacement is a promising therapy for MPS I though immunologic complications may occur.

Comparative efficacy of topically applied flurbiprofen, diclofenac, tolmetin, and suprofen for the treatment of experimentally induced blood-aqueous barrier disruption in dogs

OBJECTIVE

To compare the relative efficacies of 4 topical nonsteroidal anti-inflammatory drugs at preventing blood-aqueous barrier (BAB) disruption in dogs.

DESIGN

1 eye of each dog was treated with 1% suspensions of diclofenac, flurbiprofen, suprofen, or tolmetin, or with control solution. After 4 applications of eyedrops at 10-minute intervals, BAB disruption was induced in the treated eye by anterior chamber paracentesis. The severity of BAB disruption was measured by anterior chamber fluorophotometry.

ANIMALS

40 ocular-normal dogs.

PROCEDURE

After pretreatment with eyedrops, rapid 100-microliters nonleaking anterior chamber paracentesis was performed in 1 eye of each dog to induce BAB disruption. 1 day after paracentesis, 1 ml of 10% fluorescein sodium was injected i.v.. The amount of fluorescein entering the anterior chamber of each eye was measured 30 to 60 minutes later by use of a computerized scanning fluorophotometer. The degree of BAB disruption was determined by comparing the amount of fluorescein entering the aqueous humor of the paracentesed eye with that of the nonparacentesed eye.

RESULTS

At postparacentesis day 1, the order of statistically significant BAB-stabilizing efficacy among groups was: diclofenac > flurbiprofen > suprofen > tolmetin = control solution.

CONCLUSIONS

Topically applied 1% suspensions of diclofenac, flurbiprofen, and suprofen are effective at preventing BAB disruption after paracentesis in dogs, indicating their potential usefulness for treatment of prostaglandin-mediated ocular disease. 1% tolmetin is no more effective than control solution.

The early management of pelvic and acetabular fractures

One hundred consecutive referrals with pelvic and acetabular fractures treated over a three year period were reviewed with regard to their early management. Early management was subdivided into four areas: 1. initial assessment and treatment; 2. imaging; 3. referral; 4. management of associated injuries. The cases comprised 26 pelvic fractures (18 treated operatively), 69 acetabular fractures (50 treated operatively), and 5 combination fractures (3 treated operatively). Guidelines were laid down in each of the four areas of management and each patient's management was compared with this ideal. 56% of cases had deficient management by our criteria. There were important failures in diagnosis and early treatment of these complex injuries. A set of simple guidelines is offered to help improve the situation.

Effects of blood alcohol concentrations on negative punishment: implications for decision making

OBJECTIVE

A series of studies examined how various blood ethanol concentrations influenced the effectiveness of a negative punishment procedure in a risk-taking/decision-making task. Based on the animal punishment literature plus the impression that ethanol diminishes the effects of punishment and impairs decision making, it was predicted that individuals receiving alcohol would increase their risk- taking behavior despite the presence of a negative punishment stimulus (point loss) given on a variable schedule.

METHODS

In Experiment 1, a within-subjects design with repeated measures was used where 10 male subjects played a modified computer-generated choice game under three levels of punishment certainty, three levels of punishment severity and four ranges of blood ethanol (0.00%, 0.01-0.049%, 0.050-0.099%, 0.10-0.15%)

RESULTS

Results indicated significant decreases in risk taking as either punishment certainty or severity was increased. However, no significant effects were found for ethanol, or interactions of ethanol with punishment certainty or punishment severity. Two additional studies examining aspects of the experimental procedure produced similar results

CONCLUSIONS

Overall, the results of these studies do not support the hypothesis that high concentrations of blood alcohol are sufficient in and of themselves to eliminate the suppression function of negative punishment contingencies leading to increased risk-taking behavior. The implications of these results for understanding blood alcohol effects are discussed.

Isolation and expression of three gibberellin 20-oxidase cDNA clones from Arabidopsis

Using degenerate oligonucleotide primers based on a pumpkin (Cucurbita maxima) gibberellin (GA) 20-oxidase sequence, six different fragments of dioxygenase genes were amplified by polymerase chain reaction from arabidopsis thaliana genomic DNA. One of these was used to isolate two different full-length cDNA clones, At2301 and At2353, from shoots of the GA-deficient Arabidopsis mutant ga1-2. A third, related clone, YAP169, was identified in the Database of Expressed Sequence Tags. The cDNA clones were expressed in Escherichia coli as fusion proteins, each of which oxidized GA12 at C-20 to GA15, GA24, and the C19 compound GA9, a precursor of bioactive GAs; the C20 tricarboxylic acid compound GA25 was formed as a minor product. The expression products also oxidized the 13-hydroxylated substrate GA53, but less effectively than GA12. The three cDNAs hybridized to mRNA species with tissue-specific patterns of accumulation, with At2301 being expressed in stems and inflorescences, At2353 in inflorescences and developing siliques, and YAP169 in siliques only. In the floral shoots of the ga1-2 mutant, transcript levels corresponding to each cDNA decreased dramatically after GA3 application, suggesting that GA biosynthesis may be controlled, at least in part, through down-regulation of the expression of the 20-oxidase genes.

Squamous cell carcinoma of the corneoscleral limbus in a dog

Squamous cell carcinoma is an uncommon tumor of the cornea in dogs. A 12-year-old Shih Tzu with a history of chronic keratoconjunctivitis sicca was diagnosed as having squamous cell carcinoma of the corneoscleral limbus. The lesion was treated by surgical resection and cryotherapy. One year after surgery, multiple tumors, apparently unrelated to the first tumor, appeared on the same cornea. Keratoconjunctivitis sicca may have predisposed the dog to corneal squamous cell carcinoma development.

Leukotrienes and sensory innervation in blood-aqueous barrier disruption in the dog

The effect of a specific 5-lipoxygenase inhibitor, PF5901 (5% in corn oil), on disruption of the blood-aqueous barrier (BAB) in the dog was investigated using a unilateral mild paracentesis model. BAB breakdown was quantitated using anterior chamber fluorophotometry. Fluorescence in the eyes of the PF5901 group was not statistically significantly different (P greater than 0.05) from that in the vehicle group. A tendency towards greater fluorescein concentrations was noted in the PF5901 treated eyes. It was concluded that leukotrienes are not important mediators of BAB disruption in this model and that leukotriene inhibitors may actually exacerbate disruption due to shunting of arachidonate metabolism towards the cyclooxygenase and/or epoxygenase pathways. In a second experiment, the effects of proparacaine and flurbiprofen were evaluated on blood-aqueous barrier disruption and pupil size following a more severe paracentesis. Flurbiprofen dampened both barrier disruption and the miotic response but proparacaine suppressed neither reaction, suggesting that, in the dog, prostaglandins are more important mediators of the ocular irritative response than are sensory neuropeptides.

Ocular pharmacology

Application of sound ocular therapeutic principle is more difficult in food animals than most other species. Financial or husbandry constraints limit the practitioner's ability to use the entire range of ocular drugs available or to use them with adequate frequency. These problems may be dealt with by using systemically administered drugs when effective or by employing vehicles or delivery techniques that necessitate minimal dosing frequency. By far the most important medically treatable eye disease encountered in food animal practice is IBK. Effective therapies include systemic administration of long-acting oxytetracycline, subconjunctival administration of a variety of antibiotics, or topical application of benzathine cloxacillin. Infectious conjunctivitis in sheep and goats due to a variety of agents may be treated successfully with tetracycline in most cases. Conjunctivitis and keratitis secondary to IBR virus usually are given supportive therapy only, although specific antiviral drugs have been used in the treatment of herpetic eye disease in other species. Anterior uveitis is best treated by corticosteroid and mydriatic therapy in addition to treatment of the underlying cause, if identified.

Fluorophotometric evaluation of experimental blood-aqueous barrier disruption in dogs

A protocol for performing slit-lamp fluorophotometry of the anterior chamber in dogs was established. The technique was then used to develop a model of blood-aqueous barrier disruption that can be used for comparative testing of ophthalmic anti-inflammatory drugs. It was determined that barrier disruption induced by a slow, controlled paracentesis of a small volume of aqueous humor may provide the most reliable model for drug testing. Additionally, fluorophotometry proved to be a sensitive and accurate means of detecting breakdown of the blood-aqueous barrier.

A comparison between the coupled spectrophotometric and uncoupled radiometric assays for RuBP carboxylase

The coupled spectrophotometric assay for RuBP carboxylase was compared with the conventional radiometric assay to assess the validity of its use in the measurement of initial and total activities in crude leaf extracts. At high magnesium concentrations both assays gave the same absolute values of initial and total activities, and resolved similarly the changes of total activity and activation state (ratio of initial to total activity) which occurred when the water status and light environment of leaves was altered prior to sampling. Although the magnesium concentration supporting the maximum rate of initial activity in soybean extracts was similar in the two assays, substantial differences of initial activity were observed at sub-optimal concentrations of magnesium. At low magnesium concentrations reaction rates in the spectrophotometric assay exhibited an initial phase of non-linearity which subsequently gave way to a linear rate. In contrast, reaction rates at low magnesium were linear from the time of initiation in the radiometric assay. Inclusion of EDTA in the reaction medium did, however, induce non-linear rates in the radiometric assay. The pre-addition of RUBP to extract immediately prior to dilution into the reaction medium did not eliminate the non-linearity in either assay system. The significance of these observations is discussed briefly in relation to the use of the spectrophotometric assay.

Spontaneous canine keratoconjunctivitis sicca. A useful model for human keratoconjunctivitis sicca: treatment with cyclosporine eye drops

Thirty-six sequential cases of canine keratoconjunctivitis sicca (KCS) were treated with ophthalmic cyclosporine. The effects of topical cyclosporine were twofold: (1) cyclosporine increased tear production by 5 mm/min or greater in all cases of spontaneous KCS having an initial Schirmer's Tear Test value greater than 2 mm/min and in 59% of eyes with an initial Schirmer's Tear Test value of 0 to 2 mm/min, and (2) cyclosporine caused marked regression of chronic corneal neovascularization and granulation even in eyes in which lacrimation failed to improve. Additional benefits of topical cyclosporine were reduced mucopurulent conjunctivitis, rapid healing of nonhealing corneal ulcers, and reduced dependence on frequent topical treatments of KCS. Twelve normal beagles treated with topical cyclosporine also had a reversible increase in lacrimation compared with baseline or placebo control-treated dogs.

The histopathology of freezing injury to the rat spinal cord. A light microscope study. I. Early degenerative changes

In an effort to develop a method of tissue injury which would provide a model for the study of axonal regrowth in adult mammalian central nervous system (CNS), we have analyzed the effects of freezing in the dorsal columns of more than 200 rat spinal cords. The effects of temperature and time of exposure upon the size, shape, distribution and histologic characteristics of the lesion have been assessed during the first seven days following the injury. The upper threshold for injury occurs at -3 degrees C for 15 minutes. Between -3 degrees C and -12 degrees C the tissue changes vary in extent and characteristics. Selective damage to axons and myelin occurs with sparing of the supportive cells followed by proliferation of a cellular matrix. At seven days, the lesions produced by -8 degrees C for 15 to 60 minutes have neither axons nor myelin sheaths and consist of a dense cellular matrix of macrophages and presumed glial cells. With these tissue characteristics, and the preservation of tissue continuity without obstructive barriers, this model would appear to be potentially suitable for the study of axonal regrowth potential in mammalian CNS.

Caprolactam-barbiturate interaction at the GABAA receptor complex in the guinea-pig intestine

4,6,6-Trimethylcaprolactam antagonised GABAA receptor-mediated contractile responses in guinea-pig isolated ileum, displacing the GABA dose-response curve to the right in a non-parallel manner, and causing a depression of the maximum response. Pentobarbitone not only potentiated the GABAA receptor-mediated contractions but also reversed this non-competitive antagonism by 4,6,6-trimethylcaprolactam, shifting the dose-response curve for GABA to the left and restoring the maximum response. It is conclude that this caprolactam acts at the picrotoxin-barbiturate site on the Cl(-)-ionophore complex.

Errors in differential infrared carbon dioxide analysis resulting from water vapor

Water vapor was added differentially to the gas streams entering the cells of three makes of differential infrared carbon dioxide analysers. Analyser deflections were compared with those expected from dilution of the carbon dioxide by the additional gas. Tests were made at 0, 365, and 730 cm(3) m(-3) concentrations of carbon dioxide, and with the dewpoint in one cell of the analysers held constant at 15, 20, or 25°C. None of the analysers always responded in the ways predicted from dilution. The results showed that errors of a few cm(3) m(-3) could occur in estimates of carbon dioxide differentials using the theoretical correction for dilution. Furthermore the amount of error varied with the carbon dioxide range, the difference in water content, and in some cases the dewpoint range.

Sleep-waking patterns of intact and carotid sinus nerve-transected rats during hypoxic-CO2 breathing

Two groups, each consisting of six male rats, breathed 21% O2-4% CO2 or 10% O2-4% CO2, respectively, before and after carotid sinus nerve (CSN) transection. Polygraphic recording techniques served to monitor sleep and wakefulness. The effects of these gas mixtures on the sleep-waking pattern (SWP) were studied. The SWPs of the intact and CSN-transected rats breathing 21% O2-4% CO2 were no different from rats breathing air. While breathing 10% O2-4% CO2, the greatest alteration in the rat's SWP, compared with breathing 10% O2 devoid of CO2, was in the pattern of frequency of change of states, an effect unchanged by CSN transection. We conclude that CO2 added to air did not affect the rat's SWP. However, a hypoxic-CO2 gas mixture radically altered all parameters of the SWP, an effect which was centrally mediated.

A multivariate analysis of excessive alcohol use involving labeling and self-constructs

Previous studies have focused on predicting whether or not a person is likely to become a problem drinker, but have not employed concepts explaining the process whereby excessive alcohol use emerges. It is proposed that labeling concepts, in combination with a multidimensional conceptualization of the general self-concept, provide the components of a model capable of explaining this process. Automatic Interaction Detector permitted an assessment of the contingent relationships among the labeling and self variables. The findings indicated that the influence of the alcoholic labels of others on self-views and drinking behaviors hinged on self-esteem and self-complexity.

Ovarian responses to perphenazine-induced prolactin secretion in the rats: Effect of ovulation, stress, and steroids

A single injection of 2.5 mg perphenazine (PH)/kg body wt to rats on the day of estrus (day 0) did not result in increased serum progesterone 24 hr later. Continued daily injections, however, resulted in a 2.5-fold increase in serum progesterone between days 1 and 3 and a 1.6-fold increase between days 3 and 5 to a final concentration of 58 plus or minus 4 ng/ml on day 5 in serially anesthetized and bled rats. Neither daily administration of 5.0 nor 10.0 mg PH/kg body wt to rats subjected to the stressful conditions of this regimen resulted in further increases in serum progesterone, but the 5.0 mg dose of PH in unstressed rats bled only on day 5 resulted in a highly significant increase in serum progesterone to 110 plus or minus 7 ng/ml. In unstressed rats the increase in serum progesterone over control values after five daily injections of 2.5 mg PH/kg body wt could be attributed to decreased 20alpha-reduction of progesterone, but when the dose of PH was increased to 5.0 mg/kg, a highly significant increase in both progesterone and total progestins occurred indicating that prolactin can increase steroidogenesis as well as reduce 20alpha-hydroxysteroid dehydrogenase activity. After inhibition of ovulation, the 5.0 mg daily dose of PH resulted in serum progesterone of only 25 plus or minus 8 ng/ml on day 5 in unstressed rats. Thus, serum progesterone in ovulating rats treated with PH originated primarily in the corpora lutea. Perphenazine, 5.0 mg/kg, administered only on estrus and the first day of diestrus was sufficient to induce pseudopregnancy of 14.5 plus or minus 1.6 days. No evidence for gonadotropin stimulation of the ovaries of any rats was observed. The effect of stress on the progesterone response was not mimicked by administration of cortisol acetate and is assumed to be medicated by suppression of prolactin secretion.

Differential responses of prelactating and lactating mammary gland to similar tissue concentrations of progesterone

Serum and mammary tissue concentrations of progesterone and 20alpha-hydroxy-4-pregnen-3-one (20alpha-OHP) were measured by competitive protein-binding assays and gas-liquid chromatography, respectively, in pregnant and lactating rats. The concentration of progesterone in mammary tissue of pregnant rats closely paralleled the serum concentration, particularly when tissue concentration was expressed as ng/mg DNA. The variability in tissue progesterone on the last day of pregnancy was relatively great, but there was a good inverse relation between the appearance of lactose and the progesterone concentration. Serum progesterone levels declined to their lowest values at 1-3 days of lactation (10 plus or minus 1 ng/ml); the tissue concentration declined even more rapidly after parturition. The tissue 20alpha-OHP concentration, which was more closely related to serum progesterone among animals than to serum 20alpha-OHP, remained high after parturition suggesting that the presence of 20alpha-OHP has no effect on lactogenesis and that progesterone is decreased in the tissue by 20alpha-reduction. Following postpartum ovulation, serum progesterone increased to 74 plus or minus 6 ng/ml at 6-9 days of lactation; tissue progesterone also increased to levels found in rats pregnant 14-19 days, yet no change in lactose content of the glands of suckled rats occurred, and the biosynthetic capacity in terms of the RNA/DNA ratio increased. Serum 20alpha-OHP also rose, but the tissue concentration was unchanged, suggesting that saturating levels were present throughout pregnancy and lactation. Since no rapid increase in DNA was associated with lactogenesis, differentiation of nonsecretory parenchymal cells into daughter cells with the secretory capacity must occur earlier in pregnancy. Progesterone, therefore, must inhibit lactogenesis by preventing expression of the genetic potential of daughter cells. Once differentiation has been completed, however, the presence of progesterone in the tissue has no effect on the biosynthesis of milk constituents.