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Biomedical subjects

M D Thomas

Publications and source records attributed to M D Thomas.

At least 19 recordsLinked to original sources
PubMed1992

Laparoscopic orchiectomy for unilateral intra-abdominal testis.

We present 2 cases of laparoscopic removal of a unilateral intra-abdominal testis. Removal of a unilateral intra-abdominal testis is indicated in patients more than 10 years old because the malignant potential of an intra-abdominal testis outweighs any cosmetic benefit of orchiopexy. Laparoscopic orchiectomy is a safe and effective surgical procedure for adolescents and adults with this disease entity providing outpatient therapy and prompt rehabilitation.

Adult↗
PubMed1992

Subcloning using simplified adaptor addition.

A simplified procedure for the addition of synthetic oligonucleotide adaptors to subclone DNA fragments with incompatible ends is presented. An organophosphate degradation gene on a PstI fragment was cloned into the HindIII site of the fungal vector pH1S. The opd gene specifies parathion hydrolase and was first isolated from a Flavobacterium sp. The gene was present in 12% of the plasmids recovered and was inserted in either direction with similar frequencies: 53% with the opd start codon distal to the single SalI site of pH1S and 47% in the other orientation. All enzymatic steps were carried out in a single microconcentrator eliminating DNA loss through manipulation and transfer. Normally, during adaptor or linker addition, a larger number of oligonucleotides are attached at each end of the insert DNA and must be removed before cloning. The need for enzymatic digestion to remove excess adaptors was avoided. Traditional methods have utilized phenol/chloroform extraction, ethanol precipitation, gel filtration chromatography, spermine precipitation, or preparative gel electrophoresis. Eliminating these steps resulted in a simpler, more reliable procedure.

Base Sequence↗
PubMed1991

Pressure erosion of the femoral trochlea, patella baja, and altered patellar surfaces.

As knee flexion increases, so do tendofemoral and patellofemoral compression forces. Three cases of long-standing uncorrected flexion contractures of the knees are presented that resulted in marked erosion of the femoral trochlea, patella baja, and remodeled patellar articular surfaces likely reflecting increased angles of flexion. It is probable that the deep femoral grooves are the result of adaptation under high-level persistent contact loads from the quadriceps tendon. These examples expand our knowledge of bone remodeling and offer information of potential use in studying ancient skeletal samples.

Adult↗
PubMed1991

Major salivary gland lymphoepithelial lesions and the acquired immunodeficiency syndrome.

Presently, there is no consensus regarding the most appropriate diagnostic and therapeutic approach to patients with human immunodeficiency virus (HIV)-associated lymphoepithelial lesions of the major salivary glands. A retrospective review of 60 consecutive patients with lymphoepithelial lesions is presented. Thirty-eight cases were associated with HIV infection. Lesions associated with HIV infection were usually bilateral, multiple, cystic, and associated with lymphadenopathy. In contrast, in those cases without HIV infection, the lesions tended to be solitary and solid. In the HIV-infected group, treatment included surgery, radiotherapy, zidovudine (AZT), and/or cyst aspiration. All therapeutic regimens, other than aspiration alone, were found to be effective. Eighteen of the patients with HIV infection developed the acquired immunodeficiency syndrome (AIDS) during the study period. Surgical treatment is probably not necessary in the majority of HIV-associated cases. Depending upon individual circumstances, treatment with AZT or low-dose radiotherapy is recommended. A diagnostic and therapeutic algorithm is presented as a guide to the management of future cases.

AIDS-Related Complex↗
PubMed1991

Genetic method to identify regulons controlled by nonessential elements: isolation of a gene dependent on alternate transcription factor sigma B of Bacillus subtilis.

We describe a general, in vivo method for identifying Bacillus subtilis genes controlled by specific, nonessential regulatory factors. We establish the use of this approach by identifying, isolating, and characterizing a gene dependent on sigma B, an alternate transcription factor which is found early in stationary phase but which is not essential for sporulation. The method relies on two features: (i) a plate transformation technique to introduce a null mutation into the regulatory gene of interest and (ii) random transcriptional fusions to a reporter gene to monitor gene expression in the presence and absence of a functional regulatory product. We applied this genetic approach to isolate genes comprising the sigma B regulon. We screened a random Tn917lacZ library for fusions that required an intact sigma B structural gene (sigB) for greatest expression, converting the library strains from wild-type sigB+ to sigB delta::cat directly on plates selective for chloramphenicol resistance. We isolated one such fusion, csbA::Tn917lacZ (csb for controlled by sigma B), which mapped between hisA and degSU on the B. subtilis chromosome. We cloned the region surrounding the insertion, identified the csbA reading frame containing the transposon, and found that this frame encoded a predicted 76-residue product which was extremely hydrophobic and highly basic. Primer extension and promoter activity experiments identified a sigma B-dependent promoter 83 bp upstream of the csbA coding sequence. A weaker, tandem, sigma A-like promoter was likewise identified 28 bp upstream of csbA. The csbA fusion was maximally expressed during early stationary phase in cells grown in Luria broth containing 5% glucose and 0.2% glutamine. This timing of expression and medium dependence were very similar to those for ctc, the only other recognized gene dependent on sigma B.

Amino Acid Sequence↗
PubMed1991

On public sector psychosocial nursing: a conceptual framework.

1. Nursing practice is driven more by its environment than by knowledge provided by faculty or even strong relationships between faculty and staff. Because that environment is publicly supported, programs reflect changes in the ideological environment. 2. The psychosocial nursing specialty incorporates psychiatric/mental health nursing and social sciences to reduce the negative environmental influences while increasing the positive ones. 3. Public sector psychosocial nurses must be familiar with changing laws and regulations as well as the history of hospital and community programs for the mentally ill; understand the complexity of society and that the state hospital is only one component of a large system; and contribute to the development of their subspecialty.

Health Facility Environment↗
PubMed1990

Intrahospital relocation of psychiatric patients and effects on aggression.

Aggression is a recurring problem with psychiatric patients and can pose special problems on inpatient units. The purpose of this study were to identify changes in patients aggression as a consequence of routine individual relocation and to identify the relationship of certain variables with patterns of aggression. Using an adaptation of the Overt Aggression Scale (Yudofsky, Silver, Jackson, Endicott, & Williams, 1986), data were collected from the patient records of 201 individuals who had been admitted to a state hospital and subsequently transferred to another ward in the same hospital. There was a phase by day interaction with the day-to-day pattern of aggression in the pretransfer phase differing significantly from that in the posttransfer phase. The highest mean aggression for a single day was the day following transfer; the second highest was the day before transfer. There were main effects for age and number of hospital admissions.

Adult↗
PubMed1990

Forced relocation of hospitalized psychiatric patients.

By virtue of their disability and hospital program requirements, severely and chronically mentally ill patients are subject to involuntary transfer from the community to hospitals, within hospitals, between hospitals, and from hospitals to the community. These forced relocations, no matter how humanely they were initially conceived to be, have become highly routine. The consequence is loss of the sense of the patient as a human being with individual needs. This research elicited the patients' own descriptions and the meanings they attached to the experience of forced relocation. The findings point to the need for greater success of programs designed to keep patients in their home communities to the greatest extent possible. The findings also suggest the need for hospital staff to eliminate or reduce intrahospital transfers and to develop and maintain humane transfer procedures when forced relocation becomes necessary.

Adult↗
PubMed1979

Presence of chondroitin sulfate in the neuronal cytoplasm.

The distribution of glycosaminoglycans and glycoproteins has been studied in cytoplasmic and particulate fractions of neurons isolated in bulk from rat cerebrum. Lysis of the neurons in 25 mM sodium phosphate buffer at pH 7.5 released 20% of the protein and over 90% of the lactate dehydrogenase in a soluble form. Eighty-two percent of the chondroitin sulfate was also released, together with 55% of the heparan sulfate and 24-25% of the hyaluronic acid and glycoproteins. The chondroitin sulfate remaining in the membranes was completely depolymerized to disaccharides after treatment with chondroitinase ABC, and treatment of the neuronal membranes with 0.1% trypsin removed 55-63% of the chondroitin sulfate and heparan sulfate but only 25% of the sulfated glycoproteins. The results reported here support our previous conclusion that the soluble chondroitin sulfate proteoglycan of brain is largely a cytoplasmic constitutent of neurons (and astrocytes) and is not primarily present in nervous tissue as an extracellular ground substance.

Animals↗
PubMed1976

Judgments of educators and child-care personnel about appropriate treatment for mentally retarded or normal, overactive or withdrawn, boys.

Special educators and child-care personnel ranked the appropriateness of various psychological treatments for a boy described either as mentally retarded or of normal intelligence and whose behavior was described either as withdrawn or overactive. The predicted IQ level by behavior interaction was found only for drug treatment, which was ranked as relatively more appropriate for the retarded overactive child (p less than .05). Drug treatment and behavior modification were perceived as more appropriate for the overactive child (p less than .01, .05). Play therapy, family therapy, and no treatment were deemed more appropriate for the withdrawn child (p less than .05). Educators favored behavior modification and school consultation more than did child-care personnel (p less than .05).

Allied Health Personnel↗
PubMed1976

Shunt blockage in hydrocephalic children: the use of the valvogram.

Shunt blockage in valve-dependent hydrocephalic children is not always recognised, as symptoms may be non-specific and signs inconclusive. Valvography is a simple, easily interpreted technique for the investigation of shunt patency in children with Spitz Holter values in the shunt system. The technique affords a simple, rapid method of demonstrating patency at the cardiac end of the shunt. Fifty-one valvograms have been performed in 36 children. In 25 obstruction of the lower end was demonstrated. The unreliability of some associated signs is demonstrated. No serious complications have been observed and the technique has proved an invaluable addition to the practical management of these children.

Catheterization↗