Analysis of upper and lower extremity peripheral nerve injuries in a population of patients with multiple injuries

BACKGROUND

The purpose of this study was to determine the prevalence, cause, severity, and patterns of associated injuries of limb peripheral nerve injuries sustained by patients with multiple injuries seen at a regional Level 1 trauma center.

METHODS

Patients sustaining injuries to the radial, median, ulnar, sciatic, femoral, peroneal, or tibial nerves were identified using a prospectively collected computerized database, maintained by Sunnybrook Health Science Centre, and a detailed chart review was undertaken.

RESULTS

From a trauma population of 5,777 patients treated between January 1, 1986, and November 30, 1996, 162 patients were identified as having an injury to at least one of the peripheral nerves of interest, yielding a prevalence of 2.8%. These 162 patients sustained a total of 200 peripheral nerve injuries, 121 of which were in the upper extremity. The mean patient age was 34.6 years (SEM +/- 1.1 year), and 83% of patients were male. The mean injury severity score was 23.1 (+/-0.90), and the mean length of hospital stay was 28 days (+/-1.8).

CONCLUSIONS

Motor vehicles crashes predominated (46%) as the cause of injury. The most frequently injured nerve was the radial nerve (58 injuries), and in the lower limb, the peroneal nerve was most commonly injured (39 injuries). Diagnosis of a peripheral nerve injury was made within 4 days of admission to Sunnybrook Health Science Centre in 78% of the cases. Surgery was required to treat 54% of patients. Head injuries were the most common associated injury, occurring in 60% of patients. Other common associated injuries included fractures and dislocations. The present report aims to aid in identification and treatment of peripheral nerve injuries.

Glucocorticoid exposure in utero: new model for adult hypertension

Hypertension is strongly predicted by the combination of low birthweight and a large placenta. This association could be due to increased fetal exposure to maternal glucocorticoids. Fetal protection is normally effected by placental 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD), which converts physiological glucocorticoids to inactive products. We found that rat placental 11 beta-OHSD activity correlated positively with term fetal weight and negatively with placental weight. Offspring of rats treated during pregnancy with dexamethasone (which is not metabolised by 11 beta-OHSD) had lower birthweights and higher blood pressure when adult than did offspring of control rats. Increased fetal glucocorticoid exposure secondary to attenuated placental 11 beta-OHSD activity may link low birthweight and high placental weight with hypertension.

Sexual negotiation in the AIDS era: negotiated safety revisited

OBJECTIVE

To test the safety of the 'negotiated safety' strategy-the strategy of dispensing with condoms within HIV-seronegative concordant regular sexual relationships under certain conditions.

METHOD

Data from recently recruited cohort of homosexually active men (Sydney Men and Sexual Health cohort, n = 1037) are used to revisit negotiated safety. The men were surveyed using a structured questionnaire and questions addressing their sexual relationships and practice their own and their regular partner's serostatus, agreements entered into by the men concerning sexual practice within and outside their regular relationship, and contextual and demographic variables.

RESULTS

The findings indicate that a significant number of men used negotiated safety as an HIV prevention strategy. In the 6 months prior to interview, of the 181 men in seroconcordant HIV-negative regular relationships, 62% had engaged in unprotected anal intercourse within their relationship, and 91% (165 men) had not engaged in unprotected anal intercourse outside their relationship. Of these 165 men, 82% had negotiated agreements about sex outside their relationship. The safety of negotiation was dependent not only on seroconcordance but also on the presence of an agreement; 82% of the men who had not engaged in unprotected anal intercourse outside their regular relationship had entered into an agreement with their partner, whereas only 56% of those who had engaged in unprotected anal intercourse had an agreement. The safety of negotiation was also related to the nature of the safety agreement reached between the men and on the acceptability of condoms. Agreements between HIV-negative seroconcordant regular partners prohibiting anal intercourse with casual partners or any form of sex with a casual partner were typically complied with, and men who had such negotiated agreements were at low risk of HIV infection.

CONCLUSIONS

The adoption of the strategy of negotiated safety among men in HIV-seronegative regular relationships may help such men sustain the safety of their sexual practice.

Pathophysiology of chest pain in patients with cardiomyopathies and normal coronary arteries

To clarify the pathogenesis of chest pain in patients with cardiomyopathies, we compared coronary blood flow and other indicators of ischemia at rest and during pacing-induced tachycardia in nine patients with cardiomyopathy (four hypertrophic and five congestive) and in five control subjects. Coronary blood flow was reduced at rest and during pacing in cardiomyopathy patients compared with controls. In patients with hypertrophic cardiomyopathy, pacing induced chest pain in all, increased ST-segment depression in three patients and increased coronary venous lactate concentration. With pacing, two of five patients with congestive cardiomyopathy had chest discomfort and three had increased ST-segment depression, but coronary venous lactate concentration did not change significantly. In both groups of cardiomyopathies, the ratio of the systolic and diastolic pressure-time indexes tended to decrease more than in controls during pacing. Thus, myocardial perfusion is decreased in patients with cardiomyopathy, both at rest and during pacing. The changes detected during pacing point to subendocardial ischemia as the likely mechanism for angina in hypertrophic and possibly also in congestive cardiomyopathy.

Complication rate of coronary arteriography. A review of 5250 cases studied by a percutaneous femoral technique

Distressing rates of embolic complications from coronary arteriography performed by the percutaneous femoral approach have been reported since 1972. From 1970-1974, 5250 patients underwent coronary arteriography in our laboratory by the same percutaneous femoral technique with preformed polyethylene catheters and no systemic heparinization. Data were recorded during and for 24 hours postcatheterization. The annual mortality rate averaged 0.23% and remained relatively stable. Our incidence of embolic complications was very low. In patients with normal coronary arteries, no fatal or serious nonfatal complications occurred. Left main coronary artery disease was present in all cases of mortality and greater than or equal to 60% stenosis was shown in nine of 12 instances. Thus major risk was proportional to the severity of disease in the left coronary system. The use of more aggressive supportive measures in these high-risk cases appears essential to reduce the total complication rate from coronary arteriography significantly.

Lack of tissue glucocorticoid reactivation in 11beta -hydroxysteroid dehydrogenase type 1 knockout mice ameliorates age-related learning impairments

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) intracellularly regenerates active corticosterone from circulating inert 11-dehydrocorticosterone (11-DHC) in specific tissues. The hippocampus is a brain structure particularly vulnerable to glucocorticoid neurotoxicity with aging. In intact hippocampal cells in culture, 11beta-HSD-1 acts as a functional 11beta-reductase reactivating inert 11-DHC to corticosterone, thereby potentiating kainate neurotoxicity. We examined the functional significance of 11beta-HSD-1 in the central nervous system by using knockout mice. Aged wild-type mice developed elevated plasma corticosterone levels that correlated with learning deficits in the watermaze. In contrast, despite elevated plasma corticosterone levels throughout life, this glucocorticoid-associated learning deficit was ameliorated in aged 11beta-HSD-1 knockout mice, implicating lower intraneuronal corticosterone levels through lack of 11-DHC reactivation. Indeed, aged knockout mice showed significantly lower hippocampal tissue corticosterone levels than wild-type controls. These findings demonstrate that tissue corticosterone levels do not merely reflect plasma levels and appear to play a more important role in hippocampal functions than circulating blood levels. The data emphasize the crucial importance of local enzymes in determining intracellular glucocorticoid activity. Selective 11beta-HSD-1 inhibitors may protect against hippocampal function decline with age.

Percutaneous transluminal coronary angioplasty for chronic total coronary arterial occlusion

Experience is reported with 100 consecutive patients in whom percutaneous transluminal coronary angioplasty (PTCA) was attempted on chronically occluded coronary arteries that had no visible anterograde flow. Ninety-eight patients had angina and all had collateral vessels to the occluded artery on angiography. A movable guidewire/dilatation system was used in all cases. Overall initial PTCA success rate was 56% and was related to duration of occlusion (69% success rate for occlusions of 1 month or less, 50% for 1 to 6 months and 11% after 6 months). Complications were minor; no patient died or required emergency bypass operation. Of the 44 patients in whom PTCA failed, 20 underwent elective bypass surgery for relief of angina and 24 were treated medically. Follow-up at a mean of 8 months (range 1 to 48) was available for 49 of the 56 patients in whom PTCA was successful: 40 had subjective improvement, 6 no change and 3 felt worse. Control angiography was carried out in 40 of the 56 patients with primary success and showed long-term success in 18 and reocclusion or significant stenosis in 22. Of these 22, 11 were successfully treated by a second PTCA, 2 underwent operation and 9 were treated medically. Recanalization of totally occluded coronary arteries with no forward flow has a lower initial success rate (56%) than PTCA for stenoses and the recurrence rate is higher (55%), but effective relief of angina is achieved in successful cases. The risk of serious complications appears to be low.

Rupture of the calcaneal tendon. The early and late management

We have reviewed 106 patients after treatment for spontaneous rupture of the calcaneal tendon, and assessed the clinical results including the power of plantarflexion. In patients treated within 48 hours of injury the result was very similar in conservatively and in operatively treated patients. The incidence of major complications was higher after operation (17%) than in those treated conservatively (4%). Patients who were treated more than one week after injury, however, had an inferior result with respect to power of plantarflexion after conservative management. It is therefore recommended that calcaneal tendon rupture is treated conservatively with a plaster in full equinus when it is diagnosed within 48 hours of injury, and by operation when diagnosis has been delayed for more than one week.

Diabetes mellitus in the aetiology of Dupuytren's disease

In controlled clinical studies of adult diabetics a 42% incidence of signs of Dupuytren's disease was found. The incidence was highest in the older patients with a longer history of diabetes, but was not related to the severity of the diabetes. The features of Dupuytren's disease in the diabetics has a distinctive pattern, being more severe in men than women and, compared with controls, having a radial shift towards the middle finger. The disease was mild and of benign prognosis, rarely needing operation. In a further study, 13% of patients with Dupuytren's disease were found to have a raised blood glucose level. The question is posed as to whether the biochemical disturbance causes the Dupuytren's disease or whether the pattern of inheritance predisposes to both Dupuytren's disease and diabetes.

In defence of the meniscus. A prospective study of 200 meniscectomy patients

Of 250 patients scheduled for meniscectomy 50 had symptoms which subsided and operation could be deferred; of the remaining 200 only 73 per cent were found to have a significant tear. It is shown that the risks of removing a normal meniscus far exceed those of leaving a tear in the posterior third. Statistical analysis of clinical features revealed no reliable diagnostic pattern.

An evaluation of suture materials used in tendon surgery

The following suture materials have been evaluated for their suitability for use in flexor tendon repairs: 4/0 gauge monofilament and multifilament stainless steel, mono-filament nylon, monofilament polypropylene, monofilament polybutestor, braided polyester, braided polyglycolic acid and a monofilament polyglyconate. These were investigated for their tensile strength (both knotted and unknotted), their extension to failure and knot-holding properties. Stainless steel and monofilament polyglyconate appeared to be the most suitable in that they had high tensile strengths, both knotted and unknotted, and had good knot-holding security. The only disadvantages are that stainless steel is difficult to use and monofilament polyglyconate is absorbable. Polypropylene and braided polyester, although having lower tensile strengths, are reasonable alternatives.

A tissue-culture model of cartilage breakdown in rheumatoid arthritis. Quantitative aspects of proteoglycan release

1. The destruction of articular cartilage in human rheumatoid and other arthritides is the result of diverse mechanical, inflammatory and local cellular factors. A tissue-culture model for studying cartilage-synovial interactions that may be involved in the final common pathway of joint destruction is described. 2. Matrix breakdown was studied in vitro by using bovine nasal-cartilage discs cultivated in contact with synovium. Synovia were obtained from human and animal sources. Human tissue came from patients with ;classical' rheumatoid arthritis, and animal tissue from rabbits with antigen-induced arthritis. 3. Cartilage discs increased their proteoglycan content 2-3-fold during 8 days in culture. Proteoglycan was also released into culture medium, approx. 70% arising from cartilage breakdown. 4. Synovial explants from human rheumatoid and rabbit antigen-induced arthritis produced equivalent stimulation of proteoglycan release. After an initial lag phase, the breakdown rate rose abruptly to a maximum, resulting in a 2-fold increase of proteoglycan accumulation in culture medium after 8-10 days. 5. High-molecular-weight products shed into culture media were characterized chromatographically and by differential enzymic digestion. Proteoglycan-chondroitin sulphate accounted for 90% of the released polyanion, and its partial degradation in the presence of synovial explants was consistent with limited proteolytic cleavage. 6. Rheumatoid synovium applied to dead cartilage increased the basal rate of proteoglycan release. Living cartilage was capable of more extensive autolysis, even in the absence of synovium. However, optimal proteoglycan release required the interaction of living synovium with live cartilage. These findings support the view that a significant component of cartilage breakdown may be chondrocyte-mediated.

Type 2 diabetes and late-onset Alzheimer's disease

BACKGROUND/AIMS

To confirm in a cohort recruited in 1999-2001 our finding in a cohort recruited in 1992-1994 relating type 2 diabetes (T2D) to late-onset Alzheimer's disease (LOAD).

METHODS

Participants were 1,488 persons aged 65 years and older without dementia at baseline from New York City. T2D was ascertained by self-report. Dementia and LOAD were ascertained by standard research procedures. Proportional hazard regression was used for analyses relating T2D and LOAD.

RESULTS

The prevalence of T2D was 17%. There were 161 cases of dementia and 149 cases of LOAD. T2D was related to dementia (hazard ratio = 1.7; 95% confidence interval = 1.4-2.9) and LOAD (1.6; 1.0-2.6) after adjustment for age, sex, education, ethnic group and apolipoprotein E ε4. This association was weaker when only AD - excluding cases of mixed dementia - was considered (hazard ratio = 1.3; 95% confidence interval = 0.8-2.2).

CONCLUSION

T2D is associated with LOAD. Cerebrovascular disease may be an important mediator.

Dehydroepiandrosterone 7-hydroxylase CYP7B: predominant expression in primate hippocampus and reduced expression in Alzheimer's disease

Neurosteroids such as dehydroepiandrosterone (DHEA), pregnenolone and 17beta-estradiol are synthesized by cytochrome P450s from endogenous cholesterol. We previously reported a new cytochrome P450 enzyme, CYP7B, highly expressed in rat and mouse brain that metabolizes DHEA and related steroids by hydroxylation at the 7alpha position. Such 7-hydroxylation can enhance DHEA bioactivity in vivo. Here we show that the reaction is conserved across mammalian species: in addition to mouse and rat, DHEA hydroxylation activity was present in brain extracts from sheep, marmoset and human. Northern blotting using a human CYP7B complementary deoxyribonucleic acid (cDNA) probe confirmed the presence of CYP7B mRNA in marmoset and human hippocampus; CYP7B mRNA was present in marmoset cerebellum and brainstem, with lower levels in hypothalamus and cortex. In situ hybridization to human brain revealed higher levels of CYP7B mRNA in the hippocampus than in cerebellum, cortex, or other brain regions. We also measured CYP7B expression in Alzheimer's disease (AD). CYP7B mRNA was significantly decreased (approximately 50% decline; P<0.05) in dentate neurons from AD subjects compared with controls. A decline in CYP7B activity may contribute the loss of effects of DHEA with ageing and perhaps to the pathophysiology of AD.

The effects of intrathecal midazolam on sympathetic nervous system reflexes in man--a pilot study

Nine patients were given intrathecal injections of midazolam (dose 0.3-2 mg dissolved in 3 ml 5% dextrose). No changes in motor power or general sensation were produced. Resting heart rate and blood pressure were unchanged and normal valsalva manoeuvres were elicited 30 min post-injection. Cardiovascular responses were provoked at a light plane of anaesthesia by intubation of the trachea and manipulation of peritoneum and bowel but not by surgical incision of the skin. Intrathecal administration of midazolam relieved post-operative pain of somatic origin but not of visceral origin. It is concluded that intrathecal midazolam in the dosage used interrupts somatic nociceptive afferent pathways but not abdominal visceral nociceptive afferent pathways.

Meniscal pathology and osteoarthritis of the knee

The relationship between meniscal tearing and degenerative joint disease was studied by macroscopic examination of 115 knees at necropsy. The incidence of meniscal pathology was 57 per cent. There was no overall difference in the severity and distribution of tibiofemoral degeneration, whether the meniscus was torn or normal. We found little evidence that degenerative meniscal tears cause osteoarthritis or vice versa.

Impact of adrenalectomy on 5-HT6 and 5-HT7 receptor gene expression in the rat hippocampus

Both glucocorticoid excess and decreased serotonergic (5-HT) transmission may cause depression. The recently cloned 5-HT6 and 5-HT7 receptors have high affinity for antidepressants. Here, we show that pharmacological adrenalectomy increases 5-HT6 and 5-HT7 receptor mRNA expression in specific hippocampal subfields, effects partly reversed by corticosterone replacement. Increased 5-HT6 and 5-HT7 receptor expression may provide a basis, in part, for the therapeutic actions of adrenal steroid synthesis inhibitors in resistant depression.

Dermal wound repair: role of collagen matrix implants and synthetic polymer dressings

The effects of two different polymeric wound dressings and a new collagen matrix (CM) implant on the healing and scarring of full-thickness excision wounds were studied in swine. The synthetic polymers comprised an occlusive O2-impermeable hydrocolloid dressing (HCD) and an occlusive O2-permeable polyurethane film (PUF). The CM implant consisted of an acellular collagen sponge fabricated from purified bovine tendon type I collagen. Wounds were evaluated for granulation tissue--production capacity by measuring 14C proline incorporation into collagenase-sensitive protein. Epidermal resurfacing and wound contraction were measured by computerized morphometric image analysis of wounds made on a tattooed grid. In comparison with air-exposed wounds, the relative collagen synthetic capacity was greater in the granulation tissue of wounds treated with HCD, PUF, or CM with occlusion. Both HCD and PUF accelerated by 40% the epidermal resurfacing over the granulating wound bed. Wound contraction was significantly reduced by CM but was not altered by the occlusive dressings.

5'-heterogeneity of glucocorticoid receptor messenger RNA is tissue specific: differential regulation of variant transcripts by early-life events

Glucocorticoid receptor (GR) gene expression is regulated in a complex tissue-specific manner, notably by early-life environmental events that program tissue GR levels. We have identified and characterized several new rat GR mRNAs. All encode a common protein, but differ in their 5'-leader sequences as a consequence of alternate splicing of, potentially, 11 different exon 1 sequences. Most are located in a 3-kb CpG island, upstream of exon 2, that exhibits substantial promoter activity in transfected cells. Ribonuclease (RNase) protection analysis demonstrated significant levels of six alternate exons 1 in vivo in rat, with differences between liver, hippocampus, and thymus reflecting tissue-specific differences in promoter activity. Two of the alternate exons 1 (exons 1(6) and 1(10)) were expressed in all tissues examined, together present in 77-87% of total GR mRNA. The remaining GR transcripts contained tissue-specific alternate first exons. Importantly, tissue-specific first exon usage was altered by perinatal environmental manipulations. Postnatal handling, which permanently increases GR in the hippocampus, causing attenuation of stress responses, selectively elevated GR mRNA containing the hippocampus-specific exon 1(7). Prenatal glucocorticoid exposure, which increases hepatic GR expression and produces adult hyperglycemia, decreased the proportion of hepatic GR mRNA containing the predominant exon 1(10), suggesting an increase in a minor exon 1 variant. Such tissue specificity of promoter usage allows differential GR regulation and programming.