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Biomedical subjects

D Riggs

Publications and source records attributed to D Riggs.

14 recordsLinked to original sources
PubMed1995

Apolipoprotein E and B alleles in Parkinson's patients.

Parkinson's patients were genotyped for the apolipoprotein E alleles as well as polymorphisms at the apolipoprotein B loci to determine whether they were at risk for late onset Alzheimer's disease or coronary disease. The Parkinson's patients were at no greater risk for either disease than were the control spouses. The frequency for the APOE4 allele was 11% compared with the spouses, 10%. Interestingly, 20% of the patients had the 2/3 genotype which may have a protective effect from late onset Alzheimer's disease.

Aged↗
PubMed1995

Association of apolipoprotein E but not B with Alzheimer's disease.

In our studies apolipoprotein E4 (APOE4) is associated with both early- and late-onset Alzheimer's disease. Alzheimer's patients from West Texas were screened for the APOE4 allele, which was found at frequencies of 0.43 and 0.59 in familial late- and early-onset cases. Sporadic cases had lower frequencies, but they still were 2-4 times higher than control spouses. To determine whether the APOE association may be a risk factor for coronary disease as well, we examined two APOB gene restriction sites that have previously been found to be associated with coronary artery disease, especially myocardial infarctions. The APOB alleles were found at similar frequencies in Alzheimer's patients and control spouses.

Aged↗
PubMed1994

Autopsies and the pediatric intensive care unit.

The pediatric autopsy can provide great benefits to families at a time when their world is falling apart. It can be invaluable in the processing of grief that families endure, helping them to plan their future. Autopsy results not only provide information but may also provide consolation by giving the family the opportunity to discuss the disease process that resulted in death. Autopsy results also provide information regarding the future and reassurance that appropriate care was given. Failure to perform a postmortem examination denies the family and the clinician knowledge regarding mechanisms of disease, confirmation or inclusion of unsuspected diagnoses, and the presence of iatrogenic complications. This missed information can be both informative to the current family's situation and potentially therapeutic in future cases. If death is the final chapter of life, then the physician's responsible relationship with the parents of the deceased patient should not end until a conference takes place several weeks or months after the child's death. The results of the postmortem examination provide a beginning point for discussion regarding the child's illness and death, the parents responses and coping, and the opportunity to help the family make sense of and bring closure to one of life's greatest crises.

Autopsy↗
PubMed1991

Acute hemorrhagic diarrhea and cardiovascular collapse in a young child owing to environmentally acquired cocaine.

Acute crack cocaine intoxication has become a significant problem in both adolescent and adult patients. Recently, cases of cocaine toxicity in infants and toddlers have been described. We report a four-year-old child with acute hemorrhagic diarrhea and shock after intoxication by crack cocaine. Acute cocaine intoxication should be considered in the differential for hemorrhagic diarrhea and shock. The gastrointestinal decontamination following cocaine ingestion is discussed.

Child, Preschool↗
PubMed1990

Acute toxicity from oral ingestion of crack cocaine: a report of four cases.

We report the symptomatology, clinical, and laboratory findings in four patients following oral ingestion of crack cocaine. All of the patients had a positive urine test for cocaine metabolites measured by gas chromatography-mass spectroscopy. Retrospective analysis of the four patients revealed alterations in function of the cardiovascular system (4), the autonomic nervous system (4), the central nervous system (3), and the gastrointestinal system (1). Three patients ingested crack cocaine as a direct result of confrontation with law enforcement officers. The symptomatologies of acute toxicity from oral ingestion of crack cocaine are related to its effect on the cardiovascular system and the brain. Cocaine toxicity should be considered in patients with acute and unexplained cardiovascular, central nervous system, or gastrointestinal complaints. Law enforcement personnel should be made aware of the signs and symptoms of cocaine intoxication and be made aware of the propensity to ingest the evidence.

Acute Disease↗
PubMed1989

Gene replacement and retrieval with recombinant M13mp bacteriophages.

We have developed an allele exchange system for shuttling sequences of DNA to and from their original chromosomal loci. Cloned segments of the histidine operon of Salmonella typhimurium and the lactose operon of Escherichia coli served as target sequences and were used to develop the system. Replacement and retrieval of target sequences used the phage M13mp vectors and proceeded through an M13 lysogen intermediate. The intermediates and products of allele exchange were characterized by genetic and hybridization analyses. Several unique properties of M13 lysogens were exploited to devise positive selections to detect integration and excision. These positive selections were used to manipulate phenotypically silent alleles.

Chromosome Deletion↗
PubMed1989

Resolution of impaired pulmonary function and pulmonary hypertension after phorbol ester administration in rabbits.

To assess metabolic functions of the pulmonary circulation during lung injury and subsequent recovery from injury, we measured angiotensin-converting enzyme (ACE) activity by means of benzoyl-phenylalanyl-alanyl-proline (BPAP) hydrolysis and 5-hydroxytryptamine (5-HT) removal in vivo in three groups of anesthetized rabbits. One group was treated with 30 micrograms/kg/day phorbol myristate acetate (PMA) intravenously 10 times over 14 days (PMA group). A second group received the same PMA treatment but was not studied until 14 days after the last treatment (PMA/recovery group). A third group was treated with vehicle alone. At the end of PMA treatment, rabbits had an elevated pulmonary artery pressure and depressed ACE activity, expressed as the ratio Vmax/Km. Decreased Vmax/Km for ACE was due to a significant reduction in apparent Vmax for BPAP (control = 235 +/- 37, PMA = 139 +/- 12 nmol/s). Km was unchanged (control = 25 +/- 4, PMA = 31 +/- 7 microM). Uptake of 5-HT was unaffected by PMA treatment. After 2 wk of recovery (PMA/recovery group), pulmonary hypertension had resolved. In this group, Vmax for BPAP hydrolysis was not significantly different from control (280 +/- 18 nmol/s), but Km was significantly increased (48 +/- 5 microM). We conclude that repeated exposure of rabbits to PMA results in lung injury manifested as depressed pulmonary ACE activity and pulmonary artery hypertension. Although much of these alterations were reversible within 2 wk after discontinuing PMA, an increase in apparent Km of ACE may be a more persistent alteration in vascular endothelial cell dysfunction.

Animals↗
PubMed1988

Pulmonary angiotensin-converting enzyme kinetics after acute lung injury in the rabbit.

Depression of lung endothelial cell metabolic function may be an early and sensitive indicator of lung damage. When such functions are measured in vivo, substrates injected usually must be limited to "trace" doses due to the significant hemodynamic effects of high doses of substrate. Under first-order conditions (i.e., trace doses) the enzyme or transport system rate constant Vmax/Km may be calculated, but independent estimates of each variable (Vmax and Km) are not available. We therefore used multiple indicator-dilution methods and higher substrate concentrations to apply a mathematical model, based on saturable kinetics that yield independent estimates of the apparent kinetic parameters Vmax and Km for pulmonary angiotensin-converting enzyme (ACE). We used the ACE substrate, [3H]benzoyl-phenylalanyl-alanyl-proline ([3H]BPAP) and made these measurements and also estimates of serotonin [5-hydroxytryptamine (5-HT)] removal, before and after acute lung injury induced by intratracheal administration of phorbol myristate acetate (PMA). PMA significantly depressed the percent 5-HT removal (62 +/- 3 to 44 +/- 4%) and BPAP percent metabolism (74 +/- 2 to 66 +/- 2), when trace amounts of either compound were injected as a bolus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

The hisD-hisC gene border of the Salmonella typhimurium histidine operon.

We have sequenced the hisD-hisC gene border of the Salmonella typhimurium histidine operon. The translation termination codon of the hisD gene overlaps with the translation initiation codon of the hisC gene in the manner AUGA. The Shine-Dalgarno sequence of the hisC gene is contained entirely within hisD and there is no intercistronic space since all of the bases are utilized in coding. Two mutations that alter the hisD-hisC gene border are analyzed. Both mutations simultaneously abolish the termination codon of hisD and modify the initiation codon of hisC. One of the mutations changes the hisC initiation codon from AUG to AUU. The AUU codon is 10 to 20% as efficient as AUG for initiation of translation of the hisC gene. The mutant hisC ribosome binding site is compared to the ribosome binding site of the Escherichia coli infC gene which has been reported to contain an AUU initiation codon. The role of overlapping termination/initiation codons in regulating translation of polycistronic mRNAs in bacterial operons is discussed.

Amino Acid Sequence↗
PubMed1983

Abdominal wound closure using a nonabsorbable single-layer technique.

A continuous 1-layer abdominal closure using number 2 polypropylene was employed in 200 unselected consecutive patients. All the patients had lower midline incisions and were high-risk, and the majority (82%) had some form of gynecologic malignancy. A significant number had received preoperative radiotherapy (22.5%), another 18% were obese (over 90 kg), and 15% had undergone bowel surgery. The complete evisceration rate in the series was 0. A total of 17 (8.5%) wound infections occurred and 10 (5%) postoperative ventral hernias were seen over a 2-year period. Five of these were incisional and 5 were paraincisional; 1 of each required surgical repair. The method is simple, time-saving, and successful; it carries a low complication rate for patients at high risk for postoperative evisceration.

Abdomen↗