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Biomedical subjects

J A Martin

Publications and source records attributed to J A Martin.

At least 19 recordsLinked to original sources
PubMed1995

Preliminary estimates of the incidence and consequences of tooth fracture.

The authors studied all tooth fractures identified within a two-week period among adult enrollees in a dental health maintenance organization to determine the incidence and severity of this condition. They found complete fracture rates of 5.0 and 4.4 per 100 adults per year for all teeth and for posterior teeth, respectively, with 15 percent of fractures resulting in pulpal involvement or extraction. These estimates, the first to be reported, provide information that is potentially useful to patients and dentists making decisions about treatment intended to prevent tooth fracture.

Adult↗
PubMed1992

Probing the bradykinin receptor: mapping the geometric topography using ethers of hydroxyproline in novel peptides.

Five decapeptides were prepared, each having the generic primary sequence D-Arg0-Arg1-Pro2-Hyp3-Gly4-Thi5-Ser6-X7 -Y8-Arg9. A C-terminal beta-turn was anticipated when X was an alkyl ether of D-4-hydroxyproline in either the cis or trans geometric state and Y was either a Tic or Oic residue. Whereas cis ethers have only very weak receptor affinities, the trans ethers are significantly more potent in binding to guinea pig smooth muscle having Ki values as low as 0.16 nM. Notably, these peptides do not contain a D-aromatic amino acid at position 7 of the primary sequence.

Amino Acid Sequence↗
PubMed1992

Battered children grown up: a follow-up study of individuals severely maltreated as children.

Despite intensive research interest, the field of child abuse has produced few long-term follow-up studies. This paper describes the adult functioning of a group of 19 individuals who were severely battered as young children. Results indicate highly variable outcomes for the group: Some individuals exhibited limited autonomy and few adult coping skills while others were raising families, holding jobs, and maintaining functional social ties. There was little evidence of overt aggression in the group but resentment and suspiciousness scores were high. Many subjects maintained ties with their troubled parents while others sought out birth parents after losing contact with them in childhood. Several had developed long-term stable marriages, and social supports appeared adequate for most subjects in the group. Overall, study findings indicate that early abusive trauma and adult functioning have no simple relationship.

Adaptation, Psychological↗
PubMed1992

Recent advances in the design of HIV proteinase inhibitors.

Inhibition of HIV proteinase is currently one of the most widely studied approaches for chemotherapeutic intervention in the treatment of AIDS. A range of inhibitors of this essential enzyme has been designed from detailed knowledge of its mechanism of action and cleavage sites. These inhibitors have been classified according to their derivation. All are transition-state analogues and contain a hydroxyethylene, hydroxyethylamine, phosphinate or symmetrical moiety. Many of these inhibitors have high selectivity for the viral enzyme and significant antiviral activity. Advances in the design of HIV proteinase inhibitors that have been reported in the past year are reviewed.

Amino Acid Sequence↗
PubMed1992

Phylogenetic studies of ribosomal RNA variation in higher moths and butterflies (Lepidoptera: Ditrysia).

The selection of exemplars has been shown both theoretically and empirically to affect tree topology, but the importance of the number and nature of taxa used to represent higher taxonomic lineages in molecular studies is rarely stressed. In our rRNA study of higher moths and butterflies (Lepidoptera: Ditrysia), the selection of different exemplars and outgroups caused major tree rearrangements. We also examined the effectiveness with which conserved rRNA regions track the diversification of Lepidoptera. Homoplasy is as prevalent at the few variable sites of conserved regions (18E, 18J, 28F) as at the many variable sites of a more rapidly evolving region (28B). Finally, 28B sequence variation differs qualitatively among lepidopteran superfamilies of presumed comparable age, the Papilionoidea (true butterflies) and Noctuoidea (cutworm moths and relatives).

Animals↗
PubMed1992

Allergy to amoxicillin in patients who tolerated benzylpenicillin, aztreonam, and ceftazidime.

The usual battery of skin tests employed for determining penicillin allergy may fail to detect allergic reactions to side chain-specific beta-lactam agents. We report the cases of six patients who experienced anaphylactic reactions after treatment and challenge with amoxicillin but who tolerated parenteral challenges with benzylpenicillin, aztreonam, and ceftazidime. Results of skin tests for amoxicillin (10 mg/mL) were positive for four of the six patients.

Adolescent↗
PubMed1992

Bronchial asthma induced by chick pea and lentil.

Allergic reactions to legumes through inhalation have rarely been described. We report the case of a 20-year-old man who experienced asthmatic attacks when exposed to the steam from cooking either chick pea or lentil. Type I hypersensitivity to the antigens in these legumes was demonstrated by means of immediate skin reactivity, histamine release tests, RAST and RAST inhibition. Specific bronchial challenges with the heated (75 degrees for 30 min) extracts of chick pea and lentil elicited isolated immediate responses.

Adult↗
PubMed1992

Hypersensitivity to trimethoprim.

We present two patients who experienced life-threatening immediate reactions and one patient who developed generalized urticaria following oral administration of trimethoprim (TMP) and sulfamethoxazole (SMX) combination. Skin prick tests with TMP were positive in the three patients. No patients reacted to skin prick tests with SMX. No significant levels of IgE antibodies to TMP were found by RAST in the serum of the patients. Normal subjects used as controls did not react to any of these tests. Single-blind, placebo-controlled oral challenges were positive with TMP and negative with SMX in all patients. These results suggest that the three patients developed type I hypersensitivity reactions to TMP. In our patients skin prick tests with TMP were useful in TMP hypersensitivity diagnosis.

Adult↗
PubMed1992

Clinical and genetic heterogeneity in X-linked deafness.

The use of molecular techniques in respect of the rare X-linked non-syndromic form of genetic deafness demonstrates that this is a genetically heterogeneous disorder, with evidence for at least two separate gene loci on the X chromosome. Audiological heterogeneity in this condition is emphasized by the observation of both mixed deafness and sensorineural deafness in pedigrees showing evidence for linkage to Xq13-q21. The importance and shortcomings of the audiogram in assessing females who are known gene carriers is discussed.

Adolescent↗
PubMed1991

The inhibitory activity of a peptide derivative against the growth of simian immunodeficiency virus in C8166 cells.

The peptide derivative Ro 31-8959 is a potent and selective inhibitor of the aspartic proteinases encoded by HIV-1 and HIV-2 and it arrests the growth of both viruses in cell culture. We have demonstrated similar effects against the simian immunodeficiency virus SIVmac251 in the human T-cell line, C8166 (ED50 = 6nM) with a therapeutic index of 4,500. The antiviral activity of Ro 31-8959 was 250 and 22 times greater than that of ddI and ddC, respectively. The mode of action was confirmed by accumulation of the polyprotein p55 with concomitant reduction of the cleavage product, p27, and by the production of immature virions.

Animals↗
PubMed1991

Ureteral triplication and ureterocele: report of 3 cases and review of the literature.

We report 3 cases of ureterocele associated with ureteral triplication and review the literature. Ureteral triplication was type I in 2 patients and type II in 1. Diagnosis was established preoperatively in 2 cases and intraoperatively in 1. All patients were initially treated by upper pole partial nephrectomy and aspiration of the ureterocele, leaving the ureteral stump open in the retroperitoneum. Subsequent excision of the ureterocele and ureteral reimplantation for persistent ipsilateral vesicoureteral reflux and recurrent urinary tract infections were required in 2 cases.

Child, Preschool↗
PubMed1991

The student-initiated, faculty-assisted system of evaluation of clinical teaching at the University of Virginia.

The University of Virginia School of Medicine has developed a student-initiated, faculty-assisted system to evaluate the faculty who teach the third-year clinical clerkships. All students complete an evaluation at the end of each clerkship, and the fourth-year class and student government compile the results and publish a detailed annual report of the data, offering constructive criticism and recommendations for change. Teaching faculty then review the report and respond to the student government, the faculty clerkship committee, and the student curriculum committee, addressing the contents of the report and initiating proposals to correct deficiencies and improve teaching. The experience of the first two administrations of this system (1988-1990) has been encouraging, and the authors suggest that the system will be applicable to the evaluation of clinical teaching on a universal basis.

Clinical Clerkship↗
PubMed1991

Mizoribine serum levels associated with enterotoxicity in the dog.

To prevent or minimize mizoribine enterotoxicity in organ transplant recipients and to differentiate mizoribine enterotoxicity from other causes of enteritis, serum levels of mizoribine that produced subclinical and clinical signs of enterotoxicity were determined in the dog. When mizoribine was administered orally at 12-hr intervals, half the dogs studied showed clinical evidence of gastrointestinal disturbances (vomiting, diarrhea, and anorexia) without histopathologic signs of enterotoxicity. Using a 24-hr oral-dose schedule, clinical signs of gastrointestinal disturbances and histopathologic evidence (mucosal degeneration, crypt degeneration, and necrosis) of enterotoxicity were encountered when the mean 12-hr mizoribine serum level was 0.97 +/- 0.4 microgram/ml or greater. Histopathologic signs of enterotoxicity with repeated positive fecal occult blood assays and without clinical signs of gastrointestinal disturbances occurred when the mean 12-hr serum level was 0.53 +/- 0.17 microgram/ml or greater. Oral administration of cyclosporine did not exacerbate mizoribine enterotoxicity in the dog when administered with mizoribine at a dose that produced histopathologic signs of enterotoxicity.

Animals↗
PubMed1991

D-Arg[Hyp3-Thi5-D-Tic7-Tic8]-bradykinin, a potent antagonist of smooth muscle BK2 receptors and BK3 receptors.

D-Arg[Hyp3-Thi5-D-Tic7-Tic8]-bradykinin (NPC 16731) inhibited bradykinin (BK) binding and BK-induced contraction in guinea-pig ileum, being markedly more potent than D-Phe7-BK analogues as a BK2 receptor antagonist. In isolated trachea NPC 16731, unlike other BK2 antagonists, inhibited BK binding and BK-induced contraction, and 45Ca2+ efflux in tracheal smooth muscle cells. That NPC 16731 potently inhibits BK effects in trachea provides further evidence for the existence of the airway BK3 receptor.

Amino Acid Sequence↗