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Biomedical subjects

M D Baker

Publications and source records attributed to M D Baker.

At least 109 records · Page 6Linked to original sources
PubMed1988

Pitfalls in the use of clinical asthma scoring.

We evaluated the correlation of the Wood-Downes-Lecks clinical asthma score (CAS) with outcome in 210 consecutive known asthmatic children presenting to an urban emergency department for treatment of acute asthma. All children received standard treatment consisting of administration of beta-adrenergic agents and theophylline compounds. Clinical asthma scores were assigned before each treatment phase and before disposition from the emergency department. Ten-day follow-up information was collected on each patient by telephone. While no differences in pretreatment CASs were found between outcome groups, disposition CASs were found to be significantly higher in patients eventually admitted to the hospital as opposed to those discharged home. However, CASs were not effective in identifying either those patients who required prolonged hospitalization (greater than 24 hours) or those who sustained ongoing disability following discharge home from the emergency department. These data indicate that the CAS alone is not a reliable indicator of severity of acute asthma of childhood as judged by subsequent disability.

Asthma↗
PubMed1988

Homologous recombination can restore normal immunoglobulin production in a mutant hybridoma cell line.

We report here the occurrence of homologous recombination between transferred and chromosomal immunoglobulin genes. Specifically, we have corrected a chromosomal immunoglobulin gene mutation by transferring pSV2neo vectors encoding the constant region of the immunoglobulin mu heavy chain to mutant hybridoma cells that bear a 2-base-pair deletion in the third constant region exon of their chromosomal mu gene. After DNA transfer, we detected G418-resistant transformants that produce normal IgM. Analysis of the DNA structure of the mu gene in these transformants indicates that in four of five cases the mu gene has been restored as a result of the integration of a single copy of the transfer vector by a reciprocal homologous recombination event; the fifth case seems to have resulted from gene conversion or double crossover. These results suggest that this technology might be adapted for mapping immunoglobulin gene mutations by marker rescue and for more convenient engineering of specifically altered immunoglobulin.

Animals↗
PubMed1988

A comparative study of benzoyl peroxide and clindamycin phosphate for treating acne vulgaris.

A water based 5% benzoyl peroxide gel (Benzac W5) was compared with topical 1% clindamycin phosphate solution (Cleocin T) in the treatment of acne vulgaris using a randomized, investigator blind study design. Lesion counts were significantly reduced in both treatment groups over the 12-week study period; however, the reduction of total lesions produced by benzoyl peroxide gel was significantly greater than that produced by clindamycin phosphate (P less than 0.05). Clindamycin phosphate had a milder effect on the skin surface in terms of peeling and drying than the benzoyl peroxide gel.

Acne Vulgaris↗
PubMed1988

Homologous recombination between transferred and chromosomal immunoglobulin kappa genes.

Homologous recombination between transferred and chromosomal DNAs provides a means of introducing well-defined, predetermined changes in the chromosomal genes. Here we report that this approach can be used to specifically modify the immunoglobulin genes in mouse hybridoma cells. The test system is based on the Sp6 hybridoma, which synthesizes immunoglobulin M (kappa) specific for the hapten 2,4,6-trinitrophenyl (TNP). As recipient cells, we used the Sp6-derived mutant hybridoma igk14, which has a deletion of the kappa TNP gene and consequently does not synthesize TNP-specific immunoglobulin M. igk14 retains the mu TNP gene and two additional rearranged kappa genes, denoted kappa M21B1 and kappa M21G. As a transfer vector, we used pSV2neo bearing the functionally rearranged TNP-specific V kappa segment. Following DNA transfer by electroporation, we isolated rare transformants which produced normal amounts of the functional kappa TNP chain. Analysis of the DNA of these transformants indicated that in all cases, a functional kappa TNP gene had been formed as the result of a homologous integrative recombination event with the igk14 kappa M21B1 gene. These results suggest that homologous recombination might be used for mapping and introducing immunoglobulin gene mutations and for more conveniently engineering specifically altered immunoglobulins.

Animals↗
PubMed1988

Subjective effects of humidification of oxygen for delivery by nasal cannula. A prospective study.

Humification of oxygen prior to administration by nasal cannula is an expensive practice which has been justified on the basis that it improves the comfort of patients receiving supplemental oxygen therapy. Routine humidification of low-flow oxygen (less than or equal to 4 L/min) delivered by nasal cannula has recently been challenged based on theoretic grounds and on the results of a clinical study. Nevertheless, we found, in a telephone survey of medium-sized American hospitals, that routine humidification of nasal cannula oxygen remains a common practice. To further evaluate the necessity of oxygen humidification, we prospectively evaluated, on a daily basis, the subjective complaints of consecutive patients in our institution who were ordered to receive nasal oxygen at relatively high flow rates (5 L/min). Of the 185 patients evaluated over a period of three wintertime months, 99 received humidified oxygen and 86 received dry oxygen. Complaints, especially dry nose and dry throat (42.9 percent and 43.9 percent of the daily interviews, respectively) were common in both groups, but the symptoms were relatively mild and did not increase significantly when oxygen was administered without prior humidification. We conclude that routine humidification of oxygen for administration by nasal cannula is not justifiable, and that cessation of this practice would result in significant reductions in both time and material costs in respiratory care.

Aged↗
PubMed1988

Thermal epiglottitis after swallowing hot beverages.

Two young children who sustained thermal injuries to the epiglottis (or "thermal epiglottitis") after swallowing hot beverages are reported. Findings, clinically and radiologically, in both children were similar to acute infectious epiglottitis. Children with these injuries are at risk for significant upper airway obstruction which may progress for several hours. Children in whom thermal epiglottitis is suspected should be approached with the same caution and preparedness for emergency airway management and pediatric intensive care afforded those with acute infectious epiglottitis.

Beverages↗
PubMed1987

Human bites in children. A six-year experience.

Three hundred twenty-two human bites in children, occurring during a six-year period, were reviewed. The majority occurred during warm-weather months between 2 PM and 11 PM. The upper extremities (42%), face and neck (33%), and trunk (22%) were most commonly bitten. At the time of injury, children were most often engaged in fights (61%) or play (26%). Seventy-five percent of wounds were superficial abrasions, 13% were punctures, and 11% were lacerations. None of the 242 abrasions became infected as opposed to 38% of the punctures and 37% of the lacerations. Other factors associated with increased risk of infection were delay in initial physician assessment beyond 18 hours after injury, location of the bite on the upper extremities, and occurrence of injury during sports activities. Prophylactic use of penicillin was probably not effective in reducing infection rates in these children; however, prospective data are needed to properly address this issue.

Adolescent↗
PubMed1987

Comparison of in vivo effects of intravenous infusion of N-formyl-methionyl-leucyl-phenylalanine and phorbol myristate acetate in rabbits.

Comparison of the physiologic responses in rabbits to the intravenous infusion of two polymorphonuclear neutrophil (PMN) activators, N-formyl-methionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA), has revealed marked differences in kinetics for activation between these agents. FMLP infusion was associated with maximally increased respiratory rates (RR), a maximally decreased mean blood pressure (MBP), and a maximally decreased absolute granulocyte count (AGC), all within the first 5 min after infusion. However, there were no significant differences between RR, MBP, and AGC of FMLP-treated animals and controls, 15 min postinfusion and after. On the other hand, PMA did not cause significant changes in RR or MBP until 30 min and 2 h postinfusion, respectively. Previous work has demonstrated that both FMLP and PMA stimulate the PMN metabolically in vitro via the same respiratory burst enzyme, NADPH oxidase, but that each of these activators demonstrates kinetics which are different from the other. Thus, these data from an in vivo study support previous in vitro findings and offer further evidence that the neutropenia and cardiopulmonary alterations following intravenous infusion of FMLP and PMA may be caused by metabolic activation of the blood PMN.

Animals↗
PubMed1987

Pediatric outpatient intravenous rehydration.

There is considerable variation in emergency department practices concerning the use of intravenous (IV) rehydration. Sixty-eight patients seen in a pediatric emergency room and requiring IV rehydration were studied prospectively. Fifty-eight patients were rehydrated in the emergency room, and 10 were admitted for rehydration. Fluid resuscitation ranged from 14 to 103 ml/kg (mean, 40 ml/kg). Following emergency department rehydration, two patients required subsequent emergency department rehydration, and one patient was admitted for rehydration. To determine outpatient IV rehydration practices, 214 pediatric training programs were surveyed. Of 173 respondents, 77 (44.5%) carry out IV rehydration in the emergency department in less than 5% of cases, and 115 (66.4%) perform it in less than 10% of cases; only 11.7% of programs carry out IV rehydration in the emergency department in most cases requiring such therapy. It is concluded that from the standpoints of cost effectiveness and patient acceptance, outpatient IV rehydration should be considered more often as a treatment option.

Adolescent↗
PubMed1987

Foreign bodies of the ears and nose in childhood.

The epidemiology and management aspects of 212 consecutive cases of foreign bodies of the ears and nose in children presenting to an urban pediatric walk-in and emergency care facility were retrospectively reviewed. The items most commonly removed from children's external auditory canals were roaches, paper wads, toy parts, earring parts, hair beads, eraser tips, and food. Foreign bodies most often found in the nose included hair beads, toy parts, paper wads, and food. Approximately 90% of all foreign bodies were able to be removed without significant complications by emergency department personnel with simple equipment. Those who required referral for otorhinolaryngologic intervention had more often failed at self or parental home foreign body removal attempts than those who were able to managed successfully by emergency department personnel. Parents should be cautioned against attempting to remove objects not readily visible or not capable of being grasped easily.

Adolescent↗
PubMed1987

Childhood fever: correlation of diagnosis with temperature response to acetaminophen.

Many people believe that temperature response to antipyretics in febrile children varies according to diagnosis. To evaluate the validity of this premise, we prospectively studied the temperature response to acetaminophen of febrile children who came to an urban pediatric emergency and walk-in facility. The study group consisted of 1,559 patients between the ages of 8 weeks and 6 years whose temperatures when seen were greater than 38.4 degrees C and who had not received antipyretic treatment within the previous four hours. Acetaminophen (15 mg/kg) was administered to each child and repeat temperatures were taken one and two hours later. Patient management was unaffected by the study, and physicians were unaware of the repeat temperature measurements. Telephone follow-up was conducted with the parents of each child within five days of the initial visit. Children with cultures positive for bacterial disease or chest x-ray films positive for pneumonia had slightly greater one- and two-hour temperature decreases compared with children with other diagnoses. Although statistically significant, we do not consider these differences in response to be clinically useful. We conclude that fever response to acetaminophen is not a clinically useful indicator by which to differentiate the causes of febrile illnesses in young children.

Acetaminophen↗
PubMed1986

A region of the immunoglobulin-mu heavy chain necessary for forming pentameric IgM.

In order to define the molecular requirements for IgM pentamer formation, we have isolated several mutant hybridomas which produce predominantly monomeric IgM. For one such mutant, 102, we synthesized a cDNA clone of its mu-mRNA, and found an in-frame 39-bp deletion, which thus encodes a mu-chain lacking amino acids 550-562, a region spanning the fourth constant domain and the tail of the mu-chain. To prove that this deletion is sufficient to block pentamer formation, we used site-directed mutagenesis to construct a mu-gene lacking these 39 bp, and have shown that the expression of this altered mu-gene results in the production of monomeric IgM.

Amino Acid Sequence↗
PubMed1986

Physician coverage in the pediatric emergency room. A national survey.

Pediatric emergency services are provided by most pediatric teaching hospitals in the United States. However, little information has been published regarding staffing patterns. The present study assessed the staffing of 155 such residency programs. While two thirds of the programs provide 24-hour on-site resident coverage in their pediatric emergency rooms, only 10% utilize attending pediatricians on a similar basis. Although coverage increases with increasing training-program size and emergency-room patient volume, the majority (79%) of even the largest residency programs do not provide 24-hour attending pediatrician coverage in the emergency room. Administrators of pediatric residency programs are urged to improve the staffing of their emergency rooms to include attending pediatricians on a 24-hour basis.

Emergency Service, Hospital↗
PubMed1986

Analysis of hybridoma mutants defective in synthesis of immunoglobulin M.

Hybridoma mutants defective in the expression of IgM have been analyzed by molecular and somatic cell hybridization techniques. The frequency of kappa light-chain mutants in the hybridoma PC7 was much higher than for other cell lines. In contrast to the mutations which we observed previously, the kappa mutants examined here resulted from complete or partial deletion of the kappa gene. Mutants defective in mu chain synthesis were of more diverse types including deletions, gross rearrangements, and more subtle changes. One mutant containing a cis-acting mutation resulting in reduced expression of the mu chain had an associated partial duplication of the mu gene, while others making low or undetectable levels of mu had no gross alterations in genetic structure. The usefulness of this approach to the study of gene structure and expression is discussed.

Animals↗