Total and unicondylar knee arthroplasty are equivalent treatment options in end-stage spontaneous osteonecrosis of the knee, and the size of the lesion has no influence on the results.

PURPOSE: The purpose of the present study was to compare total (TKA) and unicondylar (UKA) knee arthroplasty for spontaneous osteonecrosis of the knee (SONK), and to investigate potential correlations to radiographic parameters. METHODS: All consecutive patients with a magnetic resonance imaging (MRI) proven SONK treated with either TKA or UKA between 2002 and 2018 were analysed. The primary outcomes were postoperative complications and failure rates. Functional assessment included Knee Society Score (KSS), WOMAC Score, and range of motion. A novel three-dimensional measurement method was established to determine the size of the osteonecrotic lesion. All outcome parameters were correlated to the size of the necrotic lesion using Spearman's rank correlation. RESULTS: The two treatment groups (34 TKAs, 37 UKAs) did not differ regarding age, body mass index, and ratio of the volume of the necrotic lesion to the volume of the femoral condyle (n.s.). At a mean follow-up of 6.6 years, patients with UKA had better functional outcomes compared to patients with a TKA (WOMAC Score 1.0 vs. 1.6, p = 0.04; KSS pain 86 vs. 83, n.s), with a similar complication rate. No correlation was found between necrotic lesion size and failure rate (n.s.). CONCLUSION: UKA is a valuable treatment option for SONK leading to good functional results and a low failure rate. In case of a surgeon's concern regarding implant anchorage, TKA represents an equivalent solution. The MR-tomographic size of the osteonecrotic lesions seems to have no influence on the results. LEVEL OF EVIDENCE: III.

Factors affecting embryo production in superovulated Bos taurus cattle.

Despite a long history of bovine superovulation research, significant commercial applications did not start until the early 1970s. For some 20 years thereafter, superovulation represented the primary tool for the production of cattle embryos. In the early 1990s, commercial invitro production (IVP) was initiated in cattle. Although ovum pick-up and IVP are now commercially practiced on a wide scale, superovulation and embryo recovery by flushing remain a widespread and very effective approach to the production of cattle embryos. This review covers both the history and the effects of multiple factors on superovulation in Bos taurus cattle. There are three general protocols for suitable pre-FSH programming of donors so that gonadotrophin-responsive follicles are available. Superovulation protocols vary widely based on the FSH source, the diluent used, the number and timing of FSH injections and the timing and utilisation of various prostaglandins, controlled internal progesterone releasing devices, gonadotrophin-releasing hormone, and other means of controlling follicular development and ovulation. The number of oocytes that can be stimulated to grow and ovulate within any given donor can be estimated by either ultrasound-guided sonography or by measuring concentrations of anti-Müllerian hormone in the blood. Animal-related factors that can influence the efficacy of superovulation include cattle breed, age, parity, genetics, lactational status and reproductive history. In addition, nutrition, stress, season, climate, weather and several semen factors are discussed.

A 100-Year Review: Reproductive technologies in dairy science.

Reproductive technology revolutionized dairy production during the past century. Artificial insemination was first successfully applied to cattle in the early 1900s. The next major developments involved semen extenders, invention of the electroejaculator, progeny testing, addition of antibiotics to semen during the 1930s and 1940s, and the major discovery of sperm cryopreservation with glycerol in 1949. The 1950s and 1960s were particularly productive with the development of protocols for the superovulation of cattle with both pregnant mare serum gonadotrophin/equine chorionic gonadotrophin and FSH, the first successful bovine embryo transfer, the discovery of sperm capacitation, the birth of rabbits after in vitro fertilization, and the development of insulated liquid nitrogen tanks. Improved semen extenders and the replacement of glass ampules with plastic semen straws followed. Some of the most noteworthy developments in the 1970s included the initial successes with in vitro culture of embryos, calves born after chromosomal sexing as embryos, embryo splitting resulting in the birth of twins, and development of computer-assisted semen analysis. The 1980s brought flow cytometric separation of X- and Y-bearing sperm, in vitro fertilization leading to the birth of live calves, clones produced by nuclear transfer from embryonic cells, and ovum pick-up via ultrasound-guided follicular aspiration. The 20th century ended with the birth of calves produced from AI with sexed semen, sheep and cattle clones produced by nuclear transfer from adult somatic cell nuclei, and the birth of transgenic cloned calves. The 21st century has seen the introduction of perhaps the most powerful biotechnology since the development of artificial insemination and cryopreservation. Quick, inexpensive genomic analysis via the use of single nucleotide polymorphism genotyping chips is revolutionizing the cattle breeding industry. Now, with the introduction of genome editing technology, the changes are becoming almost too rapid to fully digest.

The effectiveness and satisfaction of web-based physiotherapy in people with spinal cord injury: a pilot randomised controlled trial.

STUDY DESIGN: A pilot randomised controlled trial. OBJECTIVES: The aims of this study were to evaluate the effectiveness and participant satisfaction of web-based physiotherapy in people with spinal cord injury (SCI). SETTING: Community patients of a national spinal injury unit in a university teaching hospital, Scotland, UK. METHODS: Twenty-four participants were recruited and randomised to receive 8 weeks of web-based physiotherapy (intervention), twice per week, or usual care (control). Individual exercise programmes were prescribed based on participants' abilities. The intervention was delivered via a website (www.webbasedphysio.com) and monitored and progressed remotely by the physiotherapist. RESULTS: Participants logged on to the website an average of 1.4±0.8 times per week. Between-group differences, although not significant, were more pronounced for the 6-min walk test. Participants were positive about using web-based physiotherapy and stated that they would be happy to use it again and would recommend it to others. Overall, it was rated as either good or excellent. CONCLUSIONS: Web-based physiotherapy was feasible and acceptable for people with SCI. Participants achieved good compliance with the intervention and rated the programme highly and beneficial for health and well-being at various states after injury. The results of this study warrant further work with a more homogeneous sample. SPONSORSHIP: This study was funded by the Queen Elizabeth National Spinal Injuries Unit, Glasgow, UK.

Embryo production with sex-sorted semen in superovulated dairy heifers and cows.

The aim of this study was to examine the effect of sex-sorted semen on the number and quality of embryos recovered from superovulated heifers and cows on commercial dairy farm conditions in Finland. The data consist of 1487 commercial embryo collections performed on 633 and 854 animals of Holstein and Finnish Ayrshire breeds, respectively. Superovulation was induced by eight intramuscular injections of follicle-stimulating hormone, at 12-hour intervals over 4 days, involving declining doses beginning on 9 to 12 days after the onset of standing estrus. The donors were inseminated at 9 to 15-hour intervals beginning 12 hours after the onset of estrus with 2 + 2 (+1) doses of sex-sorted frozen-thawed semen (N = 218) into the uterine horns or with 1 + 1 (+1) doses of conventional frozen-thawed semen (N = 1269) into the uterine corpus. Most conventional semen (222 bulls) straws contained 15 million sperm (total number 30-45 million per donor). Sex-sorted semen (61 bulls) straws contained 2 million sperm (total number 8-14 million per donor). Mean number of transferable embryos in recoveries from cows bred with sex-sorted semen was 4.9, which is significantly lower than 9.1 transferable embryos recovered when using conventional semen (P ≤ 0.001). In heifers, no significant difference was detected between mean number of transferable embryos in recoveries using sex-sorted semen and conventional semen (6.1 and 7.2, respectively). The number of unfertilized ova was higher when using sex-sorted semen than when using conventional semen in heifers (P < 0.01) and in cows (P < 0.05), and the number of degenerated embryos in cows (P < 0.01), but not in heifers. It was concluded that the insemination protocol used seemed to be adequate for heifers. In superovulated cows, an optimal protocol for using sex-sorted semen remains to be found.

Development and validation of a physical activity monitor for use on a wheelchair.

STUDY DESIGN: Keeping physically active is important for people who mobilize using a wheelchair. However, current tools to measure physical activity in the wheelchair are either not validated or limited in their application. The purpose of this study was to develop and validate a monitoring system to measure wheelchair movement. METHODS: The system developed consisted of a tri-axial accelerometer placed on the wheel of a wheelchair and an analysis algorithm to interpret the acceleration signals. The two accelerometer outputs in the plane of the wheel were used to calculate the angle of the wheel. From this, outcome measures of wheel revolutions, absolute angle and duration of movement were derived and the direction of movement (forwards or backwards) could be distinguished. Concurrent validity was assessed in comparison with video analysis in 14 people with spinal cord injury using their wheelchair on an indoor track and outdoor wheelchair skills course. Validity was assessed using intraclass correlation coefficients (ICC(2,1)) and Bland-Altman plots. RESULTS: The monitoring system demonstrated excellent validity for wheel revolutions, absolute angle and duration of movement (ICC(2,1)>0.999, 0.999, 0.981, respectively) in both manual and powered wheelchairs, when the wheelchair was propelled forwards and backwards, and for movements of various durations. CONCLUSION: This study has found this monitoring system to be an accurate and objective tool for measuring detailed information on wheelchair movement and maneuvering regardless of the propulsion technique, direction and speed.

Synthetic media for culture, freezing and vitrification of bovine embryos.

Media designed for the recovery, holding and cryopreservation of bovine and equine embryos are available from several commercial sources. In years past, some of these media contained bovine serum, although inclusion of serum in embryo transfer media is now largely discontinued due to issues relating to storage and biosecurity. Currently, bovine serum albumin (BSA) is included in most commercially manufactured media intended for use in embryo transfer (ET). Although BSA poses less risk than serum for the transmission of infectious disease, its inclusion still entails risk of viral contamination. The present review briefly describes the various components of ET media and the development of efficacious ET media containing no products of animal origin. An evaluation of the efficacy of recovery, holding, slow controlled freezing and vitrification media in both research and commercial ET embryo transfer settings is also presented.

Comparison of embryo yield and pregnancy rate between in vivo and in vitro methods in the same Nelore (Bos indicus) donor cows.

To investigate why the preferred means to produce bovine embryos in Brazil has changed from in vivo to in vitro, we compared these two approaches in the same Nelore cows (n=30) and assessed total embryo production and pregnancy rates. Without a specific schedule, all cows were subjected to ultrasound-guided ovum pick up (OPU)/in vitro production (IVP) and MOET, with intervals ranging from 15 to 45 d between procedures, respectively. To produce in vivo embryos, cows were superovulated and embryos were recovered nonsurgically from 1 to 3 times (1.4+/-0.6), whereas OPU/IVP was repeated from 1 to 5 times (3.2+/-1.2) in each donor cow during a 12-mo interval. Embryos obtained from both methods were transferred to crossbred heifers. On average, 25.6+/-15.3 immature oocytes were collected per OPU attempt. The average number of embryos produced by OPU/IVP (9.4+/-5.3) was higher (P<0.05) than the MOET method (6.7+/-3.7). However, pregnancy rates were lower (P<0.05) following transfer of IVP (33.5%) versus in vivo-derived embryos (41.5%) embryos. Embryonic losses between Days 30 and 60 and fetal sex ratio were similar (P>0.05) between in vivo and in vitro-derived embryos. We concluded that in Nelore cows, with an interval of 15 d between OPU procedures, it was possible to produce more embryos and pregnancies compared to conventional MOET.

[Conclusions and recommendations of a WHO expert consultation meeting on iron supplementation for infants and young children in malaria endemic areas]. / Conclusions et recommandations à l'issue de la consultation de l'OMS sur la lutte contre la carence martiale chez le nourrisson et le jeune enfant dans les pays d'endémie palustre.

This article presents the results of an expert consultation meeting aimed at evaluating the safety and public health implications of administering supplemental iron to infants and young children in malaria-endemic areas. Participants at this meeting that took place in Lyon, France on June 12-14, 2006 reached consensus on several important issues related to iron supplementation for infants and young children in malaria-endemic areas. The conclusions in this report apply specifically to regions where malaria is endemic.

Objective assessment of mobility of the spinal cord injured in a free-living environment.

STUDY DESIGN: An exploratory study of the practicality and feasibility of an instrument. OBJECTIVES: To adapt an activity monitor for use on a wheelchair to assess long-term mobility in a free-living environment in the spinal cord injury (SCI) population, and to explore the utility of the data collected. SETTING: Glasgow, UK. METHODS: An activity monitor was adapted for use on a wheelchair wheel. The monitor was used to assess, for 1 week, the wheelchair mobility of seven participants with SCI who only used a wheelchair. In conjunction with a second monitor on the thigh the mobility of seven participants with SCI who used a wheelchair and upright mobility, and five healthy non-wheelchair users, were assessed for 1 day. RESULTS: The adapted monitor collected 1260 h of data and was suitable for use on both manual and electric wheelchairs. During 1 week, participants with SCI who only used a wheelchair spent between 4 and 13 h moving in the wheelchair, covering a distance of between 7 and 28 km. Distinct differences in mobility were shown between participants with an SCI and non-wheelchair users. The differences in time spent in mobility activities between the groups of participants with SCI were smaller. CONCLUSIONS: The system was successfully used in this group of participants with SCI, and could provide useful information on the mobility of people with SCI in a free-living environment.

Useful 'junk': Alu RNAs in the human transcriptome.

Alu elements are the most abundant repetitive elements in the human genome; they have amplified by retrotransposition to reach the present number of more than one million copies. Alu elements can be transcribed in two different ways, by two independent polymerases. 'Free Alu RNAs' are transcribed by Pol III from their own promoter, while 'embedded Alu RNAs' are transcribed by Pol II as part of protein- and non-protein-coding RNAs. Recent studies have demonstrated that both free and embedded Alu RNAs play a major role in post transcriptional regulation of gene expression, for example by affecting protein translation, alternative splicing and mRNA stability. These discoveries illustrate how a part of the 'junk DNA' content of the human genome has been recruited to important functions in regulation of gene expression.

Carbon-activated gas filtration during in vitro culture increased pregnancy rate following transfer of in vitro-produced bovine embryos.

Many environmental conditions for in vitro embryo production (IVP) systems for cattle have been relatively standardised, e.g. media composition, temperature, pH, water quality, and atmospheric composition. However, little attention has been paid to the quality of ambient laboratory air and the gas environment in incubators. Although a few studies have examined the effects of chemical air contamination on IVP of human embryos, there are no published accounts for domestic animal embryos. Therefore, this study investigated the effects of an intra-incubator carbon-activated air filtration system (CODA) during in vitro culture (IVC) on embryonic development and subsequent pregnancy rate of bovine embryos. Immature cumulus-oocyte-complexes (COCs) were obtained twice-weekly by ultrasonic-guided transvaginal oocyte aspiration. The COCs were matured in TCM199/FCS/LH/FSH, fertilized with frozen-thawed Percoll-separated semen, and subsequently cultured for 7 day in SOFaaBSA. Day 7 embryos were transferred either fresh or frozen/thawed. The experimental design was a 2 x 2 factorial; presumptive zygotes were placed either in a conventional CO(2)-O(2)-N(2) incubator (Control group) or in an identical CO(2)-O(2)-N(2) incubator with a CODA intra-incubator air purification unit (CODA group) for IVC. The embryo production rate at Day 7 was not affected by the CODA air purification unit (23.4 and 24.7% morulae and blastocysts per oocyte for control and CODA, respectively) nor was there any significant effect on embryo stage or quality. However, the pregnancy rate was improved (P=0.043) for both fresh (46.3% versus 41.0%) and frozen/thawed embryos (40.8% versus 35.6%). In conclusion, atmospheric purification by the CODA intra-incubator air purification unit significantly increased pregnancy rate following transfer of in vitro-produced bovine embryos.

Dissecting why superovulation and embryo transfer usually work on some farms but not on others.

Bovine embryo transfer is a well-established commercial industry that is often associated with veterinary practices. Practitioners offering embryo transfer services may possess a very high standard of technical expertise; however, success in the production of embryos and the impregnation of recipients cannot be achieved unless the cattle are healthy and maintained in a well-managed cattle operation. In addition to appropriate gonadotropin treatments of donor cattle, the use of highly fertile semen, known to have been properly stored and handled is required for success. Recipient cattle must be managed with the same attention to detail as donors. Traditionally, PGF has been used for the synchronization of recipients. However, PGF is limited in its effectiveness early and late in the bovine estrus cycle. Recipient estrus synchronization with progesterone releasing intravaginal inserts has been successful and high pregnancy rates have resulted following embryo transfer.

The Holstein cow in embryo transfer today as compared to 20 years ago.

Embryo transfer practice and results were examined over a 20-year period in Holstein cows and heifers within four commercial embryo transfer programs located in different areas of North America. Mean embryo production per collection decreased (P < 0.05) in one program over time, but not in the other three. Changes in the type of cows entering embryo transfer programs, the number of times they were superstimulated and changes in the brands of gonadotropins used for superstimulation all complicated the analysis of embryo production over time. Data reveal higher pregnancy rates (P < 0.001) following transfer of embryos into Holstein heifers than into lactating dairy cows. It is not clear whether pregnancy rates have decreased over time as a result of the change from surgical to non-surgical embryo transfer. In the two programs in which pregnancy rates were analyzed, there was a decrease (P < 0.001) when non-surgical transfers were adopted in one program, while no change occurred in the other. One of the biggest changes in all programs was that more than 50% of embryos recovered from donors are now frozen after collection, whereas the majority were transferred fresh 20 years ago.

Assisted reproductive technologies in cattle: a review.

Over a period of approximately thirty years, commercial bovine embryo transfer has become a large international business. The technology is well established, and more than 500,000 embryos are produced annually from superovulated cows world wide. Since bovine embryos with intact zonae pellucidae can be specified pathogen-free through washing procedures, thousands of frozen embryos are routinely sold and transferred between countries. Throughout the world, approximately 15% of bovine embryos are produced by in vitro technology. Polymerase chain reaction technology is currently being used for sexing embryos on a small scale, and it is likely that this technology will be used for 'embryo diagnostics' in the future. Semen sexing is an established technology and is likely to be used on a small scale in the near future, especially in in vitro embryo production systems. The cloning of adult cattle through nuclear transfer and the production of cloned, transgenic cattle has been technically achieved. However, this is an expensive and inefficient technology, which is being used primarily by the pharmaceutical industry. Benefits in agriculture are likely to be minimal in the near future.

Effects of DIMBOA on detoxification enzymes of the aphid Rhopalosiphum padi (Homoptera: aphididae).

The presence of glutathione transferases and esterase activity was investigated in Rhopalosiphum padi and the effects of the cereal hydroxamic acid, 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) on these detoxification enzymes was studied. Activity of glutathione S-transferases and general esterases was determined for adult aphids feeding on a natural diet lacking DIMBOA and on an artificial DIMBOA-containing diet for 48 hours. In vivo, DIMBOA in the diet inhibited the activities of esterases by 50-75% at all concentrations tested (0.5-4 mM). The activity of glutathione transferase was inhibited to a lesser extent (30%) at the higher concentrations of DIMBOA. In vitro, DIMBOA generally inhibited the activity of esterases with an IC(50) of 33 micro M, and had a slight inhibitory effect on glutathione S-transferases. These effects of DIMBOA could make the aphids vulnerable to electrophilic agents and insecticides which may be metabolized via esterases and GSTs. In cereals, therefore, DIMBOA may act by interfering with esterase- or GST-mediated detoxification of xenobiotics by aphids.

Effect of recombinant bovine somatotropin on superovulatory response and recipient pregnancy rates in a commercial embryo transfer program.

Recombinant bovine somatotropin (rbST) has been shown to increase follicular growth in cattle and some studies have demonstrated an increase in superovulatory response for rbST-treated cows. Pregnancy rates have also been shown to increase when rbST was administered around the time of insemination or prior to embryo transfer. The application of rbST for the purpose of increasing superovulatory responses of donor cows and increasing pregnancy rates of recipient heifers was tested in a commercial embryo transfer program. In Experiment 1, embryo donor cows (n = 56) underwent three cycles of control superovulation (two before and one after weaning) and subsequently underwent up to four additional superovulations while being treated with either rbST (500 mg sustained-release rbST; Posilac, Monsanto, St. Louis, MO; n = 28) or excipient (control; n = 28) once every 14 days. In Experiment 2, lactating embryo donor cows (n = 37) underwent a control superovulation and then underwent a superovulation while lactating and being treated with either rbST (n = 16) or excipient (n = 21). In Experiment 3, embryo recipient heifers that were being implanted with either in vitro or in vivo produced embryos were treated with either rbST (n = 146) or excipient (n = 143) at the time of embryo transfer. Treatment of non-lactating (Experiment 1) or lactating (Experiment 2) donor cows with rbST during repeated superovulation did not affect the number of corpora lutea, the sum of transferable embryos, degenerate embryos, and unfertilized oocytes, or the number of transferable embryos. Treatment of recipient heifers with rbST (Experiment 3) did not affect pregnancy rates for either in vitro or in vivo produced embryos. We conclude that superovulatory response and pregnancy rates (respectively) are similar to control for rbST-treated cows undergoing repeated superovulations and rbST-treated recipient heifers treated at the time of embryo transfer.

Nonelectrophoretic PCR-sexing of bovine embryos in a commercial environment.

Techniques for sex determination of bovine embryos have evolved from karyotyping of older preimplantation embryos some 25 years ago to the current variety of widely used polymerase chain reaction (PCR) protocols. Although highly accurate, most PCR protocols for sex determination have included an electrophoresis step. The present work is a retrospective study utilizing a unique PCR protocol to sex bovine embryos without use of electrophoresis in a commercial embryo transfer program. Both in vivo and in vitro-derived embryos were produced by conventional techniques and biopsied between 7 and 8 days of age with a steel blade attached to a mechanical micromanipulator. Males constituted 49.0% of 3964 in vivo and 53.0% of 1181 in vitro-derived embryos subjected to PCR. Based on ultrasound fetal sexing and on calvings, the accuracy of sex determination was 98.7% for male embryos and 94.4% for females, with no samples producing an undetermined outcome. Pregnancy rates following transfer of biopsied Grade 1 embryos were lower than control, intact embryos as follows: 8, 6 and 16% points for in vivo, in vitro and in vivo frozen embryos, respectively. Pregnancy rates were similar for all stages of in vivo-derived embryos, whereas the pregnancy rate was significantly lower for in vitro-derived morulae compared to all stages of blastocysts. The sex ratio was significantly skewed in favor of females among in vitro-derived morulae, and in favor of males among in vitro expanded blastocysts. The sex ratio of in vivo expanded blastocysts was significantly skewed in favor of female embryos. No seasonal variation in either pregnancy rate or sex ratio was detected. There was no evidence that DNA contamination influenced the PCR assay during the duration of the study. The assay was sensitive to single blastomeres from male embryos, whereas it was not sensitive to Percoll-centrifuged or accessory sperm cells.

Proposed reductive metabolism of artemisinin by glutathione transferases in vitro.

Artemisinin is a sesquiterpene lactone containing an endoperoxide bridge. It is a promising new antimalarial and is particularly useful against the drug resistant strains of Plasmodium falciparum. It has unique antimalarial properties since it acts through the generation of free radicals that alkylate parasite proteins. Since the antimalarial action of the drug is antagonised by glutathione and ascorbate and has unusual pharmacokinetic properties in humans, we have investigated if the drug is broken down by a typical reductive reaction in the presence of glutathione transferases. Cytosolic glutathione transferases (GSTs) detoxify electrophilic xenobiotics by catalysing the formation of glutathione (GSH) conjugates and exhibit glutathione peroxidase activity towards hydroperoxides. Artemisinin was incubated with glutathione, NADPH and glutathione reductase and GSTs in a coupled assay system analogous to the standard assay scheme with cumene hydroperoxide as a substrate of GSTs. Artemisinin was shown to stimulate NADPH oxidation in cytosols from rat liver, kidney, intestines and in affinity purified preparations of GSTs from rat liver. Using human recombinant GSTs hetelorogously expressed in Escherichia coli, artemisinin was similarly shown to stimulate NADPH oxidation with the highest activity observed with GST M1-1. Using recombinant GSTs the activity of GSTs with artemisinin was at least two fold higher than the reaction with CDNB. Considering these results, it is possible that GSTs may contribute to the metabolism of artemisinin in the presence of NADPH and GSSG-reductase. We propose a model, based on the known reactions of GSTs and sesquiterpenes, in which (1) artemisinin reacts with GSH resulting in oxidised glutathione; (2) the oxidised glutathione is then converted to reduced glutathione via glutathione reductase; and (3) the latter reaction may then result in the depletion of NADPH via GSSG-reductase. The ability of artemisinin to react with GSH in the presence of GST may be responsible for the NADPH utilisation observed in vitro and suggests that cytosolic GSTs are likely to be contributing to metabolism of artemisinin and related drugs in vivo.

Genetic polymorphism of CYP2D6 and CYP2C19 in east- and southern African populations including psychiatric patients.

OBJECTIVES: The study was carried out to investigate the distribution of cytochrome P450 2D6 (CYP2D6) and CYP2C19 genotype frequencies in three African populations and to compare these frequencies between healthy individuals and psychiatric patients. METHODS: Three hundred and eighty-four subjects from South Africa (Venda), Tanzania, and Zimbabwe who consented to the study were genotyped for CYP2D6 (CYP2D6*1, *2, *3, *4, *5, and *17) and CYP2C19 (CYP2C19*1, *2, and *3) by PCR-RFLP (polymerase chain reaction restriction fragment length polymorphism) techniques. RESULTS: The genotypes for CYP2D6 predicted a poor metabolizer frequency of 2.3% (2/88) in Tanzanian psychiatric patients, 1.9% (2/106) in Tanzanian healthy controls and 2.6% (2/76) in the South African Venda. The low-activity CYP2D6*17 allele frequency was higher in psychiatric patients (30%, 53/176) than in healthy individuals (20%, 43/212) in Tanzanians. The frequencies for CYP2C19*2 genotypes were predictive of a low prevalence of poor metabolizers (PMs). The CYP2C19*3 allele was absent in the three populations studied. There was no difference in CYP2D6 or CYP2C19 PM genotype frequencies between psychiatric patients and healthy subjects. CONCLUSION: The genotype results predict a low prevalence of people with deficient CYP2D6 and CYP2C19 activity among linguistically (Bantu) related populations of East and Southern Africa. The high frequency of the low-activity CYP2D6*17 allele predicts that the Bantu people have a reduced capacity to metabolise drugs that are CYP2D6 substrates.