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Biomedical subjects

J Zahn

Publications and source records attributed to J Zahn.

13 recordsLinked to original sources
PubMed2000

Improved epidural analgesia in the parturient in the 30 degree tilt position.

PURPOSE: To compare the incidence of incomplete analgesia when epidural local anesthetic is administered with the parturient supine in a 30 degree leftward tilt or in the left lateral decubitus position. METHODS: After placement of a multiorifice catheter 5 cm into the epidural space, 293 women in active labour were randomly positioned either to the left lateral decubitus position (lateral group) or supine with a 30 degree leftward tilt (tilt group) and then received 13 mL bupivacaine 0.25%. The success of the epidural block was determined by asking the patient if she required additional medication 15 min later. The incidence of complications (fetal heart rate decelerations, hypotension, and ephedrine usage) was noted. RESULTS: In the lateral group, 38% required additional medication compared with 24% in the tilt group (P = 0.006). There were no differences between groups in the incidence of maternal hypotension or fetal heart rate decelerations, but more women (10%) received ephedrine in the lateral than in the tilt group (4%), P = 0.035. CONCLUSIONS: Placing the parturient supine with a 30 degree leftward tilt is associated with a greater success rate of labour epidural analgesia without an increase in complications than in women in the left lateral decubitus position. This advantage should be considered when positioning the parturient after epidural catheter placement.

Adult↗
PubMed2000

Comparison of non-invasive blood pressure measurements on the arm and calf during cesarean delivery.

OBJECTIVE: Shivering may occur in 75% of women undergoing spinal anesthesia for cesarean delivery and may render an automated noninvasive blood pressure (ANIBP) device incapable of determining blood pressurc (BP). When patients shiver under spinal anesthesia, the lower extremities do not exhibit the same involuntary muscle movements as do the upper extremities. This study was undertaken to determine if a correlation exists between ANIBP measurements in the arm and calf of women undergoing cesarean delivery under spinal anesthesia. METHODS: We enrolled 73 women in this blinded, prospective study. Simultaneous arm and calf BP were measured with an ANIBP and differences between the two were determined. RESULTS: We found significant differences between the average difference in systolic and in diastolic BP, no significant difference between the average mean BP, and a tendency for the systolic BP to be higher and the diastolic BP to be lower in the calf than in the arm; however, there was a large degree of variability among patients. CONCLUSION: We conclude that there is a poor correlation between the BP measured by an ANIBP on the calf and one on the arm. In the parturient undergoing cesarean section, lower extremity BP as measured by an ANIBP does not correlate with the arm ANIBP and should not be used to assure fetal well being.

Anesthesia, Obstetrical↗
PubMed1999

Epidural ropivacaine for the initiation of labor epidural analgesia: a dose finding study.

UNLABELLED: The purpose of our study was to determine the lowest concentration of ropivacaine that offers pain relief for the initiation of labor epidural analgesia. Women in active labor were enrolled in this prospective, randomized, double-blinded study to receive either ropivacaine 0.20% (Group I), ropivacaine 0.15% (Group II), or ropivacaine 0.10% (Group III). After placement of the epidural catheter, 13 mL of the study medication was administered. Fifteen minutes later, the adequacy of analgesia was assessed. If the woman reported that her degree of analgesia was not adequate, an additional 5 mL of the study medication was given, the degree of pain relief was reassessed 15 min later, and the study was concluded. A sequential study design was used to assess the success rates. We found that 26 of 28 (93%) women in Group I had adequate analgesia, compared with only 18 of 28 (64%) in Group II (P = 0.014) and 4 of 12 (33%) in Group III (P = 0.003). We conclude that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%. IMPLICATIONS: The lowest effective concentration of ropivacaine for the initiation of labor epidural analgesia has not been determined. We found that ropivacaine 0.20% offers adequate analgesia significantly more often than either ropivacaine 0.15% or ropivacaine 0.10%. If one selects ropivacaine as the sole local anesthetic for the initiation of labor epidural analgesia, the minimal concentration should be 0.20%.

Adult↗
PubMed1998

Subhypnotic doses of propofol do not relieve pruritus induced by intrathecal morphine after cesarean section.

UNLABELLED: The purpose of this study was to determine whether subhypnotic doses of propofol effectively relieve pruritus in women who received intrathecal morphine for postoperative analgesia after cesarean delivery. Twenty-nine women who developed pruritus after undergoing an elective cesarean section and receiving intrathecal morphine (0.25 mg) for postoperative analgesia were enrolled in this randomized, prospective, double-blind study. The women were randomly assigned to receive either 1 mL of propofol (n = 17) or 1 mL of placebo (n = 12) I.V. Pruritus was evaluated 5 min after treatment. In the absence of successful treatment, the women received another 1 mL of the same drug. Pruritus was again evaluated 5 min after the second dose. We found that pruritus was successfully treated twice in the propofol group and once in the placebo group (P = not significant). The antipruritic action of propofol lasted for up to 6 h in one woman and 15 min in the other. The one success in the placebo group lasted for 15 min. We conclude that the success rate of propofol in treating pruritus in women who received intrathecal morphine for postoperative analgesia after cesarean delivery is not significantly different from that of placebo. IMPLICATIONS: Pruritus is a common and bothersome side effect of neuraxial opioids after cesarean section. Subhypnotic doses of I.V. propofol (10 mg) have been used to treat pruritus caused by neuraxial opioids. In this prospective, randomized, double-blind study, we found that propofol does not relieve pruritus in women who underwent cesarean section and received intrathecal morphine sulfate (0.25 mg) for postoperative pain relief.

Adult↗
PubMed1998

Treatment of incomplete analgesia after placement of an epidural catheter and administration of local anesthetic for women in labor.

BACKGROUND: Approximately 15% of women still have pain after placement of an epidural catheter and administration of local anesthetic for labor analgesia. Two techniques frequently used to treat this pain were compared: (1) withdrawal of the catheter 1 cm and repeated dosing with additional local anesthetic, and (2) repeated dosing with additional local anesthetic without any catheter manipulation. METHODS: Fifteen minutes after placement of a multiple-orifice epidural catheter 5 cm into the epidural space and administration of 13 ml 0.25% bupivacaine to the parturient in labor, the adequacy of analgesia was assessed. All women who had incomplete analgesia were randomized (first intervention) to receive an additional 5 ml 0.25% bupivacaine (local-anestheticonly group) or to receive 5 ml 0.25% bupivacaine after first withdrawing the epidural catheter 1 cm (catheter-manipulation group). If after 15 min the woman still had pain, then (second intervention) the catheter was withdrawn 1 cm and an additional 5 ml 0.25% bupivacaine was administered to the local-anesthetic-only group, whereas 5 ml 0.25% bupivacaine was given to the catheter-manipulation group without further catheter manipulation. The success rate of the second intervention was assessed 15 min later. RESULTS: Seventy-eight women were enrolled in the study, 39 to each group. In the local-anesthetic-only group, 29 (74%) women were successfully treated with the first intervention and the remaining 10 (100%) were successfully treated with the second intervention. In the catheter-manipulation group, 30 (77%) were successfully treated with the first intervention and 7 (100%; 2 patients were not studied because of investigator error) were successfully treated with the second intervention (P=NS). CONCLUSIONS: Administration of additional local anesthetic without first withdrawing the epidural catheter will effectively treat most women for whom analgesia is incomplete after the placement of an epidural catheter during labor.

Analgesia, Epidural↗
PubMed1997

Safe epidural analgesia in thirty parturients with platelet counts between 69,000 and 98,000 mm(-3).

Regional anesthesia is a popular form of pain relief for the management of labor and delivery. Thrombocytopenia is considered a relative contraindication to the administration of regional anesthesia. Some authorities have recommended that an epidural anesthetic be withheld if the platelet count is <100,000 mm(-3). For the period of March 1993 through February 1996, we reviewed the charts of all parturients who had a platelet count <100,000 mm(-3) during the peripartum period. Eighty women met this criterion. Of these 80, 30 had an epidural anesthetic placed when the platelet count was <100,000 mm(-3) (range 69,000-98,000 mm(-3)), 22 had an epidural anesthetic placed with a platelet count >100,000 mm(-3) that subsequently decreased below 100,000 mm(-3), and 28 did not receive a regional anesthetic. We found no documentation of any neurologic complications in the medical records. We conclude that regional anesthesia should not necessarily be withheld when the platelet count is <100,000 mm(-3).

Analgesia, Epidural↗
PubMed1997

Palindrome resolution and recombination in the mammalian germ line.

Genetic instability is promoted by unusual sequence arrangements and DNA structures. Hairpin DNA structures can form from palindromes and from triplet repeats, and they are also intermediates in V(D)J recombination. We have measured the genetic stability of a large palindrome which has the potential to form a one-stranded hairpin or a two-stranded cruciform structure and have analyzed recombinants at the molecular level. A palindrome of 15.3 kb introduced as a transgene was found to be transmitted at a normal Mendelian ratio in mice, in striking contrast to the profound instability of large palindromes in prokaryotic systems. In a significant number of progeny mice, however, the palindromic transgene is rearranged; between 15 and 56% of progeny contain rearrangements. Rearrangements within the palindromic repeat occur both by illegitimate and homologous, reciprocal recombination. Gene conversion within the transgene locus, as quantitated by a novel sperm fluorescence assay, is also elevated. Illegitimate events often take the form of an asymmetric deletion that eliminates the central symmetry of the palindrome. Such asymmetric transgene deletions, including those that maintain one complete half of the palindromic repeat, are stabilized so that they cannot undergo further illegitimate rearrangements, and they also exhibit reduced levels of gene conversion. By contrast, transgene rearrangements that maintain the central symmetry continue to be unstable. Based on the observed events, we propose that one mechanism promoting the instability of the palindrome may involve breaks generated at the hairpin structure by a hairpin-nicking activity, as previously detected in somatic cells. Because mammalian cells are capable of efficiently repairing chromosome breaks through nonhomologous processes, the resealing of such breaks introduces a stabilizing asymmetry at the center of the palindrome. We propose that the ability of mammalian cells to eliminate the perfect symmetry in a palindromic sequence may be an important DNA repair pathway, with implications regarding the metabolism of palindromic repeats, the mutability of quasipalindromic triplet repeats, and the early steps in gene amplification events.

Animals↗
PubMed1993

A double-blind comparison of nimesulide and mefenamic acid in the treatment of acute upper respiratory tract infections in children.

The efficacy and safety of nimesulide suspension were evaluated in comparison with mefenamic acid in a double-blind multicentre study that recruited 100 children with acute respiratory tract infections. On entry, each child was randomly allocated to receive either nimesulide 5 mg/kg/day or mefenamic acid 5 mg/kg divided into 2 or 3 daily doses as an oral suspension, for a period of 3 to 10 days. Body temperature returned to normal on the third day for most of the nimesulide-treated patients, but only on the fifth day for the mefenamic acid group. There was a significant difference (p < 0.01) between the antipyretic activity of nimesulide and that of mefenamic acid. Furthermore, treatment with nimesulide was associated with clinically significant improvement in all inflammatory signs and symptoms observed (rhinorrhoea, nasal obstruction, pharyngeal redness, swelling of lymph nodes and cough). Adverse effects considered possibly related to treatment were recorded for 3 patients treated with nimesulide and 1 with mefenamic acid.

Acute Disease↗
PubMed1990

Usher's syndrome.

Usher's syndrome is an autosomal recessive condition of congenital sensorineural hearing loss and retinitis pigmentosa. Other abnormalities are present but inconsistently, suggesting the genetic concepts of pleiotropy and heterogeneity. Accordingly, several classifications have been suggested. Clinical findings involve the visual, auditory and vestibular systems. The identification of the carrier state would allow for more timely and accurate genetic counselling. A screening program for Usher's syndrome appears feasible. This would allow affected, deaf individuals to prepare themselves for the expected visual loss giving them a better chance for a productive, fulfilling life.

Genetic Counseling↗
PubMed1984

Hepatitis A-virus in cell culture. V. Neutralizing antibodies against hepatitis A-virus.

A test system for the detection of neutralizing antibodies against hepatitis A-virus (anti-HAV-Nt) is presented. The anti-HAV-Nt assay is performed with Frhk-4/R cells and the hepatitis A virus (HAV) strain GBM/Frhk-4/R which has been adapted to these cells. Non-neutralized HAV is demonstrated 14 days after infection of Frhk-4/R cells using a radio-immunoassay for detecting newly grown HAV. The influence of differing amounts of HAV on the anti-HAV-Nt titre and the effect of variations in incubation time of virus-serum mixtures are described. The time course of anti-HAV-Nt is shown in sera from a hepatitis-A patient which were taken at different stages of the disease. Anti-HAV-Nt is compared with anti-HAV and anti-HAV-IgM. It is shown that anti-HAV-Nt correlates closely with anti-HAV and separated anti-HAV-IgG, but only slightly with anti-HAV-IgM. The test system presented makes possible the demonstration of neutralizing antibodies against HAV in gamma-globulin preparations and during vaccination studies.

Animals↗