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Biomedical subjects

G Rubin

Publications and source records attributed to G Rubin.

At least 19 recordsLinked to original sources
PubMed1992

Using mark-recapture methodology to estimate the size of a population at risk for sexually transmitted diseases.

To study the spread of sexually transmitted diseases (STDs) using social/sexual mixing models, one must have quantitative information about sexual mixing. An unavoidable complication in gathering such information by survey is that members of the surveyed population will almost certainly have sexual contacts outside that population. The number of these outsiders may be substantial and, hence, important for the modelling process. In this paper, we develop a mark-recapture model for estimating the size of the population at risk for contracting a STD due to direct sexual contact with a specified population targeted by a survey. This mark-recapture methodology provides a reliable method of estimating the number of outsiders. Because not everyone in the targeted population may be sexually active, the size of the sexually active subset, used as the number marked in our tag-recapture formulation, must be estimated, which introduces extra variability. We derive an estimator of the variance of the estimated total number at risk that accounts for this extra variability and an expression for the bias of that estimator. We extend the methodology to stratified surveys and illustrate its use with data collected from a population of university undergraduates to estimate sexual mixing parameters of a deterministic model of the spread of STDs.

Analysis of Variance↗
PubMed1992

Effects of intramuscular administration of glycosaminoglycan polysulfates on signs of incipient hip dysplasia in growing pups.

We tested the hypothesis that treatment of growing, susceptible (to hip dysplasia) pups by IM administration of glycosaminoglycan polysulfates would mitigate the signs of incipient hip dysplasia. In 1 experiment, 7 pups, selected at random from 2 litters, were administered glycosaminoglycan polysulfates (2.5 mg/kg of body weight, IM) twice weekly, and 7 control pups from the same litters were given sterile buffered 0.9% saline solution from the age of 6 weeks to 8 months. Hip joints were examined by radiography, with pups in the standard, limbs-extended position. At 8 months of age, all pups in this experiment did not manifest femoral head subluxation radiographically. The Norberg angle, a measure of coxofemoral congruity, improved from a mean +/- SEM value of 102 degrees +/- 1 degrees in controls to 106 degrees +/- 1 degrees in treated pups (P = 0.008). Pups were not subjected to necropsy. In the second experiment, 8 pups were selected at random from 2 litters and were administered 5 mg of glycosaminoglycan polysulfates/kg, IM, twice weekly from 6 weeks to 8 months of age. Similarly, 8 control pups were administered saline solution. At 8 months of age, hip joints were examined by radiography with pups in the standard position; at necropsy, intra-articular tissues were evaluated macroscopically and biochemically. Of 8 treated pups, none had subluxation radiographically, whereas 4 of 8 control dogs had femoral head subluxation. Mean Norberg angle on the radiographs was 109.7 degrees +/- 1.6 degrees for the treated group and was 101.5 degrees +/- 1.6 degrees for controls, representing a mean improvement in coxofemoral congruity of 8.2 degrees in the treated pups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Craniocerebral epidermoids and dermoids. A review of 44 cases.

We review 40 epidermoids and 4 dermoids of the skull and brain treated surgically in our Department between 1976 and 1987. Fourteen were extradural and 30 intradural. The mean duration of symptoms was 3 years for extradural and 10 years for intradural tumours. Symptoms varied with tumour site, in some sites being helpful in differential diagnosis. Skull X-rays and CT were the key diagnostic investigations in extradural and CT in intradural lesions, the latter, with few exceptions, presenting a characteristic CT scan. In 7 cases MRI supplied important details on the tumour boundaries. All the diploic and orbital lesions were removed totally, with a good outcome. Twelve of the intradural lesions were removed totally, 9 subtotally and 9 partially, with a good outcome in 21 patients and a poor outcome in 4; 5 patients died. Outcome was unrelated to degree of removal.

Adolescent↗
PubMed1988

Isolation of a putative phospholipase C gene of Drosophila, norpA, and its role in phototransduction.

Severe norpA mutations in Drosophila eliminate the photoreceptor potential and render the fly completely blind. Recent biochemical analyses have shown that norpA mutants lack phospholipase C (PLC) activity in the eye. A combination of chromosomal walking and transposon-mediated mutagenesis was used to clone the norpA gene. This gene encodes a 7.5 kb RNA that is expressed in the adult head. In situ hybridizations of norpA cDNA to adult tissue sections show that this gene is expressed abundantly in the retina. The putative norpA protein is composed of 1095 amino acid residues and has extensive sequence similarity to a PLC amino acid sequence from bovine brain. We suggest that the norpA gene encodes a PLC expressed in the eye of Drosophila and that PLC is an essential component of the Drosophila phototransduction pathway.

Amino Acid Sequence↗
PubMed1988

Prostheses and orthoses for the foot and ankle.

The general nature and function of the AFO has been presented. These devices encompass the foot and leg crossing the ankle joint. They may insert into the shoe or attach to the shoe. The more recent AFOs are made of polypropylene and were formerly composed of steel. The indications for an AFO are for a basically ambulatory patient with problems walking, including various pathologic gaits especially drop-foot and spastic equinus. Other primary indications include ankle arthritis, Charcot foot, fractures, and post-surgery. Given the basic employment of AFOs to treat problems directly related to the foot, it is hoped that this introduction has stimulated practitioners to begin using this essential tool as an integral component of their practice.

Adult↗
PubMed1987

The risk of breast cancer in postmenopausal women who have used estrogen replacement therapy.

We studied the association between estrogen replacement therapy (ERT) and the risk of breast cancer as part of the Cancer and Steroid Hormone Study. All subjects in the analysis were postmenopausal women enrolled from eight geographic areas. Women 25 to 54 years old with newly diagnosed breast cancer were identified through population-based tumor registries and diagnosed between Dec 1, 1980, and Dec 31, 1982. Controls were selected from the same eight geographic areas by the random digit dialing of residential telephone numbers. Analyses included 1369 cases and 1645 controls. Among women with bilateral oophorectomy, the relative risk of breast cancer for women who had ever used ERT was 1.3, compared with women who had never used ERT. Among women who had undergone hysterectomy but who still had at least one ovary, the relative risk was 1.1; among women who reported a natural menopause, the relative risk was 0.8. Overall, the risk of breast cancer did not appear to increase appreciably with increasing ERT duration or latency, even for durations and latencies of 20 years or longer.

Adult↗
PubMed1987

A second opsin gene expressed in the ultraviolet-sensitive R7 photoreceptor cells of Drosophila melanogaster.

We have identified a second Drosophila opsin gene, Rh4, which is expressed specifically in the ultraviolet-sensitive R7 photoreceptor cells. The two R7 opsins, Rh3 and Rh4, are expressed in nonoverlapping subsets of R7 cells. The Rh4 opsin shares 72% amino acid identity with Rh3, but is only about 35% homologous with the other 2 Drosophila opsins, ninaE and Rh2. Twenty-eight amino acids are conserved among all 4 invertebrate and 5 vertebrate opsin genes thus far sequenced, suggesting that these residues play an important role in rhodopsin function.

Amino Acid Sequence↗
PubMed1987

Controlled tissue expansion for correcting amputation stump scar.

The authors describe the recently developed technique of tissue expansion to correct a problem-causing amputation scar. The technique involves the use of a progressively distended silicone bag placed under the skin to gradually stretch the skin so as to provide sufficient excess skin to allow plastic closure and elimination of the scarred tissue that had interfered with the use of a prosthesis.

Adult↗
PubMed1986

Serotonin-lesion myoclonic syndromes. I. Neurochemical profile and S-1 receptor binding.

This paper and the following one describe the effects of L-5-hydroxytryptophan (5-HTP) (after 3 intracisternal injections of 5,7-dihydroxytryptamine (DHT], fenfluramine (FF), p-chloroamphetamine (PCA) and drug combinations on (i) brain regional amine concentration (HPLC with LEC) and serotonin S-1 receptor binding; and (ii) 'serotonergic' behaviors in the same adult rats. Serotonin (5-HT) neurotoxins produced significantly different regional profiles of 5-HT depletion. Multiple DHT injections caused a 90-100% depletion of 5-HT concurrently in neocortex, hippocampus, striatum, septum/accumbens, pons, cerebellum, and cervical cord. Only PCA significantly depleted midbrain. Drug combinations with DHT resembled DHT alone rather than additive depletions, except for PCA + DHT, which produced a hybrid pattern of depletion. The S-1 binding assay, using cold 5-HT to displace [3H]5-HT, was performed with and without ascorbate, EDTA, CaCl2, and pargyline. Without ascorbate, binding was specific, saturable, region-dependent, and non-linear with high (Kd 1-3 nM) and low affinity (10-20 nM) components but no cooperativity (0.8 less than nH less than 1.0). Bmax and Kd did not differ significantly between vehicle- and drug-treated animals in neocortex, hippocampus, striatum, thalamus, hypothalamus, midbrain, pons, medulla, cervical cord, cerebellum, or septum/accumbens two weeks after lesioning, while the assay did detect a 60% reduction in Bmax induced by ascorbic acid (1 mM). The effects of assay conditions exceeded the changes sometimes reported in S-1 receptor Bmax after 5-HT lesions.

5,7-Dihydroxytryptamine↗
PubMed1986

Prescription of above-knee and below-knee prostheses.

New developments in socket design, materials and fabrication are briefly reviewed. A series of charts is presented which summarize the below-knee and above-knee prescription procedures followed at the Veterans Administration Prosthetics Center.

Age Factors↗
PubMed1986

Aspects of stoma care in general practice.

A survey of stoma care in general practice is reported. It demonstrates a wide diversity in the patterns of care provided to ostomates, with only half of the general practitioners reporting regular follow-up by a member of the health care team. Dealing with appliance difficulties was found to be an aspect of stoma care in which a majority of general practitioners have little confidence. The district nurse and stoma nurse are considered to be the most valuable sources of back-up. It is suggested that structured follow-up of ostomates by the primary care team might influence the level of morbidity among this group of patients.

Colostomy↗
PubMed1985

Rescue of the Drosophila phototransduction mutation trp by germline transformation.

Phototransduction is the process by which light-stimulated photoreceptor cells of the visual system send electrical signals to the nervous system. Many of the steps that follow the initial event in phototransduction, absorption of light by rhodopsin, are ill-defined. The fruitfly, Drosophila melanogaster, provides a means to dissect phototransduction genetically. Mutations such as transient receptor potential (trp) affect intermediate steps in phototransduction. In order to facilitate molecular studies of phototransduction, the trp gene was isolated and its identity was confirmed by complementing the mutant trpCM allele of the trp gene by P-element mediated germline transformation of a 7.1-kilobase DNA fragment. Expression of the trp gene begins late in pupal development and appears to be limited to the eyes and ocelli.

Animals↗