Fetal pulse oximetry: a new method of monitoring the fetus

Experimental pulse oximetry devices, similar to the existing systems used in adult and neonatal monitoring, can be used on the fetus to provide safe, and rapid information about oxygenation. They have been calibrated using fetal lambs and validated in human cross-sectional studies. Experiments have shown that fetal oxygen saturation decreases during normal labour, and drops after a uterine contraction especially with oxytocin-induced tachysystole. When the mother is given oxygen the fetal oxygen saturation increases. Readings are effected by caput and movement, and trends seem to be more meaningful than absolute values. Pulse oximetry can predict fetal outcome and a normal oxygen saturation result is specific for a good outcome perhaps even if the CTG is abnormal. However the technique is still experimental and there is insufficient data to support its use as a replacement for fetal blood sampling or a discriminator for an abnormal fetal heart trace.

Preliminary evidence from magnetic resonance imaging for reduction in disease activity after lymphocyte depletion in multiple sclerosis

The central nervous system lesions of multiple sclerosis (MS) can be detected by magnetic resonance imaging (MRI) and the initial perivascular inflammatory component is distinguished by the presence of gadolinium enhancement. To assess the effect of systemic lymphocyte depletion on disease activity, seven patients with MS received a 10-day intravenous course of the humanised monoclonal antibody CAMPATH-1H (anti-CDw52). With some variations in the protocol, enhanced cerebral MR images were obtained monthly for 3-4 months before and at least 6 months after treatment. 28 enhancing areas were detected on the first series of 7 scans; 51 additional active lesions were identified on 18 scans before treatment; 15 were detected on 20 scans done over the next 3 months, but only 2 active lesions were seen on 23 scans during follow-up beyond 3 months. The difference in lesion incidence rate before and after treatment varied and the rate ratio was significantly reduced in only three patients. Collectively, in a "meta-analysis", the rate ratios were 0.15 [corrected] (95% CI 0.09-0.24) for all seven patients and 0.24 (0.14-0.42; p < 0.001) with exclusion of the patient whose scanning schedule differed. The effect of CAMPATH-1H on disease activity provides direct, but preliminary, evidence that disease activity in MS depends on the availability of circulating lymphocytes and can be prevented by lymphocyte depletion. It is too early to say anything about the clinical results of treatment with this agent.

Formation of extrachromosomal circular DNA in HeLa cells by nonhomologous recombination

Extrachromosomal circular DNA (eccDNA) generated from chromosomal DNA is found in all mammalian cells and increases with cell stress or aging. Studies of eccDNA structure and mode of formation provide insight into mechanisms of instability of the mammalian genome. Previous studies have suggested that eccDNA is generated through a process involving recombination between repetitive sequences. However, we observed that approximately one half of the small eccDNA fragments cloned from HeLa S3 cells were composed entirely of nonrepetitive or low-copy DNA sequences. We analyzed four of these fragments by polymerase chain reaction and nucleotide sequencing and found that they were complete eccDNAs. We then screened a human genomic library with the eccDNAs to isolate the complementary chromosomal sequences. Comparing the recombination junctions within the eccDNAs with the chromosomal sequences from which they were derived revealed that nonhomologous recombination was involved in their formation. One of the eccDNAs was composed of two separate sequences from different parts of the genome. These results suggest that rejoining of ends of fragmented DNA is responsible for the generation of a substantial portion of the eccDNAs found in HeLa S3 cells.

Triplex formation by the human Ha-ras promoter inhibits Sp1 binding and in vitro transcription

The central role of the ras oncogenes in the pathogenesis of a wide variety of human malignancies is well established. Toward developing specific transcriptional inhibitors of the human Ha-ras oncogene, we have designed oligonucleotides to target a region of the Ha-ras promoter (-8 to -28) which contains two of the three Sp1 binding sites essential for transcriptional activity. Gel mobility analysis and DNase I footprinting demonstrate that an oligonucleotide (HR21ap) forms a sequence-specific triple helix with its target site in an antiparallel orientation with respect to the purine-rich duplex strand through predominantly G*G:C triplets. Within the Ha-ras promoter, HR21ap binds exclusively to the proximal target Sp1 sites over a similar nontarget distal sequence which, like the target, contains a consensus Sp1 site. Protein binding assays demonstrate that triplex formation by HR21ap inhibits Sp1 binding to the Ha-ras promoter. Moreover, oligonucleotide-directed triplex formation arrests Ha-ras promoter-dependent transcription in vitro. The results presented here suggest that triplex formation by the Ha-ras promoter targeted oligonucleotide may provide a means to specifically inhibit transcription of this oncogene in vivo.

Triumph and disaster. Early experiences in pituitary surgery

The year--1932. The place--St Vincent's Hospital, Sydney. I was a young surgeon with a sort of evangel for surgical teaching, and met regularly with a group of students in the outpatient department.

Isolation and characterization of a cDNA clone showing C-myc binding-activity

A cDNA clone encoding a novel c-myc promoter binding protein (MBP-2) was isolated from a HeLa cell expression library. MBP-2 showed binding to the sequence from -46 to -64, relative to the P2 transcription start site of the human c-myc oncogene. This important regulatory sequence is necessary for optimal transcription from the P2 promoter of the c-myc oncogene. A single base substitution prevented binding of the recombinant MBP-2 to its target sequence. The MBP-2 cDNA hybridized to a 1.7 kb transcript from several human tissues. Mouse antisera to the recombinant MBP-2 showed binding to an approximately 80 kd protein from the HeLa and NIH3T3 cell lines by Western blot analysis. Nucleotide sequence analysis suggested that MBP-2 is a unique DNA binding protein and may play an important role in the regulation of c-myc transcription.

Expression of heat shock protein 70 kDa in human endometrium of normal and infertile women

The expression of heat shock protein (hsp) 70 was investigated in endometrial samples from patients with unexplained infertility associated (n = 5) or not associated (n = 10) with endometriosis, and compared with a control group consisting of fertile women (n = 27) with reported menstrual disturbance. The expression of hsp, and in particular hsp 70, is up-regulated in response to many physico-biochemical insults as well as infection and possibly oncogenic transformation and is a good indicator of a biological system under stress. A significant over-expression of hsp 70 was found in the infertile groups (P < 0.001), suggesting that a stress response may be involved in the aetiology of unexplained infertility irrespective of the presence of endometriosis.

Laparoscopic appendectomy, is it worth it?

The recent experience with open appendectomy was compared to our initial experience with laparoscopic appendectomy. Thirty-eight patients had open appendectomy for acute appendicitis. Two major and four minor complications occurred. Concurrently, 39 patients had laparoscopic appendectomy. There was one major and one minor complication. Of the laparoscopic patients, 69% received less than 24 hours of parenteral postoperative analgesia, compared to 44% of the patients in the open group. Fifteen of 39 laparoscopic patients (38%) were discharged within 24 hours of operation versus 3 of 38 (8%) in the open group. Total mean hospital cost for the laparoscopic group, $7,500, was significantly greater than for the open group, $5,700, because of increased laparoscopic equipment charges. Both open and laparoscopic appendectomy procedures were performed with minimal morbidity. The benefits of laparoscopy were earlier hospital discharge and less parenteral analgesic use, but it was significantly more expensive.

Growth curve for Propionibacterium acnes

We established growth curves for Propionibacterium acnes isolates recovered from eyes with chronic postoperative endophthalmitis. The growth curve plotted the average of the duplicate bacterial concentration against time. The generation time for P. acnes calculated from the growth curves was approximately 5.1 hours. The growth of P. acnes is slower than other anaerobic bacteria. This may account for its delayed appearance in culture of ocular specimens. It may also explain treatment failure if the concentration of an antibiotic injected into the vitreous does not remain at an effective level during the critical replicative phase of the organism.

Mouse rump-white mutation associated with an inversion of chromosome 5

The rump-white (Rw) mutation in the mouse was previously mapped as part of a cluster of spotting genes on Chromosome (Chr) 5 that includes the dominant spotting (W) and patch (Ph) loci. Recent studies have shown that the W locus encodes the KIT tyrosine kinase cell surface receptor and that Ph is a deletional mutation encompassing the platelet-derived growth factor receptor alpha subunit (Pdgfra) gene. However, the molecular basis of the Rw mutation remains to be established. We have analyzed an interspecific Mus spretus backcross segregating Rw and several loci proximal and distal to the W/Ph/Rw region to study the basis of this mutation. These studies indicated that loci within the En2 to Kit region of the chromosome do not recombine with one another even though they have been separated in other mapping studies presented here and elsewhere. We conducted a series of fluorescent in situ hybridization (FISH) studies with genomic probes to En2, Msx1, D5Buc1, and Kit to compare the physical order of these loci on the Rw and wild-type chromosomes. The Kit locus mapped to approximately the same region on both chromosomes of the Rw heterozygotes, while the positions of En2, Msx1, and D5Buc1 were reversed on the two chromosomes. Taken together, both the genetic and physical mapping data establish that the Rw mutation is associated with an inversion involving loci in the proximal region of Chromosome 5.

The changing spectrum of fungal keratitis in south Florida

PURPOSE

To review the clinical experience with fungal keratitis in south Florida over a 10-year period.

METHODS

One hundred twenty-five cases of fungal keratitis were identified in the microbiology laboratory records between January 1982 and January 1992. The medical record of each patient was reviewed.

RESULTS

The most commonly associated risk factor was trauma (44%). Fungal keratitis developed in five patients using extended wear contact lenses and one patient wearing a therapeutic bandage contact lens. Clinical features included irregular, feathery margins (62%), a dry, rough texture (47%), and satellite lesions (41%). An initial positive culture was obtained in 90% of patients, with a majority of cultures becoming positive within 48 hours. The Fusarium sp accounted for 62% of the isolates, with Fusarium oxysporum being the most commonly isolated organism. New fungal isolates include Candida parapsilosis, Aspergillus terreus, Candida tropicalis, and Trichosporon beigellii. Natamycin 5% suspension was the initial antifungal agent used for 91% of the patients, with an average duration of treatment of 38 days. Twenty-five patients were treated with oral ketoconazole for a median duration of 2 weeks, in addition to topical antifungal therapy. Thirty-four patients (27%) required a penetrating keratoplasty. Six patients had recurrence of fungal keratitis after penetrating keratoplasty.

CONCLUSIONS

Trauma, including contact lens wear, is the most commonly associated risk factor. The fungal organisms can be readily identified in culture. F. oxysporum is the most common organism, with new isolates identified. The mainstay of therapy is topical natamycin with the increasing use of imidazoles.

Effect of abasic linker substitution on triplex formation, Sp1 binding, and specificity in an oligonucleotide targeted to the human Ha-ras promoter

A region of the human Ha-ras promoter (-8 to -28) which contains two of the three Sp1 binding sites essential for transcriptional activity forms a sequence specific oligonucleotide-directed pur*pur:pyr triple helix. The relative binding of oligonucleotides containing different substitutions, including an abasic propanediol linker, over three potentially destabilizing C:G interruptions in the otherwise poly G:poly C target was examined. DNase I footprint titrations reveal that substitution of the positively charged abasic propanediol linker results in approximately ten fold greater binding than cytosine substitution which in turn provides greater sequence specific binding than substitution of a guanine in the third strand oligonucleotide over the C:G interruptions. Protein binding assays demonstrate that triplex formation by the linker substituted oligomer (HR21Xap) is less effective in inhibiting Sp1 binding than the cytosine substituted oligomer (HR21ap) both to the target sequence as well as an upstream sequence. As an indication of the effect of linker substitution and targeting consensus Sp1 sites on triplex specificity, the relative ability of the Ha-ras promoter targeted oligonucleotides to interact with non-target Sp1 sequences within the Ha-ras promoter as well as in the DHFR promoter and HIV-1 LTR was also investigated. At concentrations which afford complete DNase I protection of the target sequence, HR21ap does not bind to the non-target sequences while HR21Xap interacts weakly only at a distal site in the DHFR promoter. Also, HR21ap as well as HR21Xap are specific in their inhibition of Sp1 binding. These results suggest that the propanediol linker is able to skip over interruptions in a target sequence thereby stabilizing triplex but, slightly compromises sequence specificity and the ability to inhibit Sp1 binding to the Ha-ras promoter.

Potential bacterial contamination of eyedrops used for tonometry

We compared the potential for bacterial contamination of a proparacaine hydrochloride solution preserved with benzalkonium chloride, which is used with fluorescein paper for tonometry, to that of a fluorescein-benoxinate hydrochloride combination solution preserved with chlorobutanol. We contaminated bottles of each solution with Pseudomonas aeruginosa or Staphylococcus aureus (10(7) organisms per milliliter of eyedrop solution). From the fluorescein-benoxinate hydrochloride solution, Staphylococcus organisms were cultured in declining numbers over time, with a half-life of nine seconds, and no Staphylococcus organisms were recovered after five minutes. Pseudomonas organisms disappeared from this solution within 15 seconds. Neither species was viable after 15 seconds in the proparacaine hydrochloride solution. Additionally, we cultured 12 bottles of fluorescein-benoxinate hydrochloride and 15 bottles of proparacaine hydrochloride that had been in use in the clinic for one month. No organisms were recovered from a drop dispensed from any bottle or from the tips, caps, rims, or solution from within any bottle, except that five colonies of Staphylococcus grew from the external rim of one bottle. We conclude that both solutions sterilize themselves rapidly and effectively. Either may be used safely for tonometry.

Blood donor counselling for HIV: results of a multi-country feasibility study

A qualitative characterisation study was conducted by the World Health Organisation's Global Programme on AIDS, and the International Federation of Red Cross and Red Crescent Societies, in six developing countries in order to determine the feasibility of introducing blood donor counselling into procedures for blood donation at blood transfusion sites. After careful preparation of consultants, in-country visits were made to include structured discussions with key BTS and Red Cross, and national AIDS programme staff, and donors, and observations of relevant facilities. Necessary resources, management requirements, obstacles to and options for blood donor counselling were explicated, together with information on the role of HIV testing in motivating blood donation, and problems associated with this and with donor notification. Blood donor counselling is seen as feasible, provided minimum conditions can be established to ensure appropriate standards and availability of resources.

Nutritional risk in New England elders

BACKGROUND

To better define nutritional risk among older Americans, a cross-sectional study of nutrition and health status was carried out in a probability sample of 1,156 free-living elders, 70 years and older, from 67 communities representing urban and rural areas of the six New England states.

METHOD

All participants completed telephone interviews concerning demographic and health characteristics. A subsample of 1,156 individuals underwent in-home assessments of oral health, anthropometrics, and nutritional risk, including a 24-hour dietary recall.

RESULTS

Nutrition-related problems were common and diverse among New England elders. Some 41.5% were overweight (BMI > 27 kg/m2), and mean dietary lipid intakes were considerably above recommended levels (Healthy People 2000 (National Health Promotion and Disease Prevention Objectives). Some 16% were underweight (BMI < 22 kg/m2), mean dietary calcium levels were low, and about 28% of older individuals failed to consume adequate levels (> 75% the Recommended Dietary Allowance for persons 51 years and older) for three or more key nutrients. Persons of advanced age or who smoked were more likely to have high dietary lipid intakes or less than adequate nutrient intake. Higher dietary lipid levels were also more common among men and individuals who lived with others. Low nutrient intake was more prevalent in those with lower educational attainment and dental problems.

CONCLUSION

Nutrition policies and multidisciplinary interventions for older Americans need to emphasize the spectrum of nutritional problems in the elderly, including dietary excesses and potential nutrient deficiencies. The demographic and life-style characteristics that place older individuals at high nutritional risk need to be considered, particularly advanced age, gender, living situation, smoking, dietary behavior, educational attainment, and dental health.

Sequential injection of 3% sodium tetradecyl sulfate and 20% sodium chloride in the treatment of refractory varicosity of the greater saphenous vein

BACKGROUND

American practitioners of sclerotherapy are limited by United States Food and Drug Administration (FDA) restrictions. The strongest FDA-approved sclerosant is sodium tetradecyl sulfate. In the United States, when a varicose vein is refractory to treatment with this drug, there are no effective FDA-approved pharmaceutical alternatives.

OBJECTIVE

A method of sequential injection of sodium tetradecyl sulfate followed immediately by sodium chloride is described. We have theorized that this drug combination should be more effective than equivalent doses of either drug alone.

METHODS

The injections are done under ultrasonic guidance. Sodium tetradecyl sulfate is injected first. After the vessel goes into spasm, a second injection of sodium chloride is made through the same needle.

RESULTS

In the majority of varicose veins that had been refractory to repeated large doses of sodium tetradecyl sulfate alone, a single sequential injection treatment has brought about sclerosis and rapid atropy.

CONCLUSION

This method should be considered for any case in which sclerotherapy is indicated, if it is known or anticipated that sodium tetradecyl sulfate alone will be ineffective or inefficient.

Differential RNA fingerprinting as a tool in the analysis of spermatozoal gene expression

The apparent decline in human male fertility and the concomitant increase in testicular pathology have prompted discussion of the underlying molecular mechanisms which may underpin these observations. While monitoring the expression of protamine-2 genes in the human ejaculate, we found a representative complement of sperm mRNAs following sequence-independent amplification of reverse-transcribed cDNAs with the polymerase chain reaction (RT-PCR). The revelation of unique sperm-derived PCR products using this method suggests that it should now be possible to investigate gene expression in human spermatogenesis by differential RNA fingerprinting of ejaculate spermatozoa. The identification of molecular markers and the corresponding genes associated with male infertility will be considerably enhanced by these investigations while obviating the requirement for invasive biopsy.

Establishing an internal medicine practice: a model to determine economic feasibility

To make informed career decisions, physicians must acquire a basic knowledge in medical management and health care economics as they evaluate the potential survival and growth of a primary care practice. Health care providers considering a specific community and local leaders and hospital administrators attempting to recruit internal medicine physicians need a method by which they can evaluate a community's potential for supporting a first or additional primary care physician. To develop this method, we conducted a detailed survey of nonmetropolitan internal medicine generalists and primary care physicians. Data collected from internal medicine physicians and their administrative staff reflected the volume of ambulatory and hospital visits and the direct and indirect costs of the practice over the previous 24 months. Using the fixed and operating cost data, as well as number of patient visits and patient care revenue, we designed a model to project the economic feasibility of establishing an internal medicine practice in a specific community. This model can be used to project the number of adult primary care visits a community can generate for a prospective physician, as well as to estimate the direct and indirect costs, annualized capital costs, gross revenue, and net income of the practice.

Canine, human, and rat plasma insulin responses to galanin administration: species response differences

Previous studies demonstrated that porcine galanin is a potent inhibitor of insulin secretion in many species but fails to alter human insulin secretion. To resolve whether this discrepancy was due to the use of a heterologous peptide or to a true species response difference, we studied the effect of a synthetic replicate of human galanin on glucose-stimulated insulin secretion in rats, dogs, and humans. On administration into rats, human and rat galanin significantly inhibited glucose-induced insulin responses to a similar degree. Similarly, porcine and human galanin significantly elevated canine plasma glucose and inhibited canine plasma insulin responses. In contrast, plasma glucose and insulin responses to glucose administration in humans were unaltered by the addition of human galanin at or above the maximum effective dose employed in dogs. Possible effects of galanin administration were seen on human glucagon and pancreatic polypeptide responses to glucose at the highest dose of human galanin infused. We conclude that galanin probably does not play a major role in modulating human beta-cell function.

Inhibition of nuclear protein binding to the human Ki-ras promoter by triplex-forming oligonucleotides

The human Ki-ras promoter contains a 22 base pair homopurine.homopyrimidine (pur.pyr) motif within a region that is nuclease-hypersensitive in both native chromatin and supercoiled plasmids. Gel mobility shift analysis and competition experiments show that this pur.pyr motif binds a nuclear protein(s) in a sequence-specific manner. Several observations suggest that the nuclear protein may be an important regulatory factor. Gel mobility shift analysis and DNase I footprinting demonstrate that oligonucleotides can be targeted to this motif forming sequence-specific purine*purine.pyrimidine (pur*pur.pyr) or mixed purine/pyrimidine*purine-pyrimidine (pur/pyr*pur.pyr) intermolecular triple helices through guanine (G) recognition of guanine.cytosine (G.C) base pairs and either adenine (A) or thymine (T) recognition of adenine-thymine (A.T) base pairs in the target sequence. Triple helices containing either T*A.T or A*A.T triplets are formed exclusively with oligonucleotides antiparallel to the homopurine target strand. The affinity of an oligonucleotide which forms T*A.T triplets is approximately equal to, or slightly greater than, the affinity of an oligonucleotide which forms A*A.T triplets. Oligonucleotide-directed triplex formation inhibits sequence-specific nuclear protein binding to the K-ras promoter. These observations suggest that triplex formation by the oligonucleotides described here may provide a means to specifically inhibit transcription of the K-ras oncogene.